Okay, a couple of days have been past now. I was using my phone back then, playing a game and then suddenly the notification led lighted blue and then the screen turned black. But it's still working. I thought it got hanged out or empty battery but it didn't show the samsung logo. So I restarted it. It started and I can unlock the lockscreen but it's all showing black screen. Can't see anything. Menu, home, power, volume and back buttons are all working.
I brought it to phone repair centers and they all said it was LCD problem and I need to pay for like $100(converted) for a new LCD. Are they saying the truth or I can still resolve this?
Yes, there seems to be a physical problem.
I cant say if its the LCD itself, or a cable, or a conector, or the graphics chip on the board. But yes, it seems to be a hardware issue.
If you are able to work on stuff like that, open the phone yourself, clean the board with Isoprophyl, clean the connectors and put it back together.
Maybe that will already fix it. If not, let them take a shot.
If you are not sure about that procedure, there are a lot of videos on youtube showing you how to dis- and reassemble an S4.
First things first, Hi
Second, Only the S4 Active has an LCD screen, the others are AMOLED.
Third, You say that all the keys are working. Are you basing this on the touch sounds, or are the any visual indicators?
what reaper said... if you go ahead and get it repaired insist that you get an AMOLED panel and not an LCD, you'll regret it if you don't...
GDReaper said:
First things first, Hi
Second, Only the S4 Active has an LCD screen, the others are AMOLED.
Third, You say that all the keys are working. Are you basing this on the touch sounds, or are the any visual indicators?
Click to expand...
Click to collapse
yes. ui touchpad works, volume buttons, power and home. i can hear the lockscreen being unlocked when i swipe it after being locked.
it's just the screen is all black.
Backe888 said:
Yes, there seems to be a physical problem.
I cant say if its the LCD itself, or a cable, or a conector, or the graphics chip on the board. But yes, it seems to be a hardware issue.
If you are able to work on stuff like that, open the phone yourself, clean the board with Isoprophyl, clean the connectors and put it back together.
Maybe that will already fix it. If not, let them take a shot.
If you are not sure about that procedure, there are a lot of videos on youtube showing you how to dis- and reassemble an S4.
Click to expand...
Click to collapse
that's what i'm guessing but i let them use my phone and see the problem and they all said LCD considering it's amoled yeah. I may try that but i need tools to open it like small screw etc..
Related
Hi all, this is my first post on this forum but I've been reading for a while to educate myself.
I've got a Herm200 that I've been trying to troubleshoot but to no avail. I'm fairly certain that it has a hardware problem but I haven't been able to isolate anything.
Here's whats happening:
Occasionally the screen will come out of stand-by all white. This will also happen randomly if i touch the screen to perform a command. While the screen is operating, sometimes the buttons on the face will stop working, however the buttons across both sides will continue working just fine.
When the screen turns all white a soft, hard, or stand-by cycle will not always bring it back to life. The fact that the hard reset wont always fix the problem makes me think it's a hardware issue since the phone will boot-up with the the all-white screen.
This is incredibly frustrating especially since HTC wont accept any warranty claims in the USA on the Tytn.
At first I thought this might be a problem with the ribon connection between the screen and the base but i haven't been able to confirm or discount anything at this point. I have yet to find a way to consistently reproduce or rectify the problem so it's very hard to troubleshoot.
I pretty much have to take a second phone with me everywhere right now just incase i need to make a call. Please help! Has anyone ever encountered such a problem?
Thank you in advance!
SneezyRobot said:
Occasionally the screen will come out of stand-by all white. This will also happen randomly if i touch the screen to perform a command. While the screen is operating, sometimes the buttons on the face will stop working, however the buttons across both sides will continue working just fine.
Click to expand...
Click to collapse
Hi. This sounds very similar to a problem that I experienced with a HERMES100. I bought the phone off someone on Ebay recently - someone had obviously scrambled the radio on it. I re-flashed it, and it sprang to life. However, after a couple of days, I experienced a problem where occasionally the LCD would stop refreshing, all the pixels faded away leaving only a white screen. Under these circumstances, some of the buttons on the phone stopped working. Turning phone on/off sometimes cured the problem, or it would require the occasional hard reset. This would happen once or twice a day and I suspect thats why someone tried to re-flash the phone.
In the end, out of curiosity I took the entire phone apart, put it all back together again and now there are no more problems!! Totally fixed!
My suspicion is that it was one of the ribbon cable push connectors on the mainboard - possibly not seated properly, or a bit of dirt contaminating the connection. Obviously when I took the phone apart I must have re-seated it.
If you are planning to take your phone apart, please exercise considerable care because some of the parts are very small and easily damaged. I would recommend buying a proper kit to take it apart. I bought mine for about £5 off ebay. Particularly useful are the plastic spoon "wedges" used to gently prise open the case after removing the screens. Don't use a screwdriver - you will scratch the case.
Good luck.
wow... that sounds like exactly what's going on here, I actually even tried to disassemble it lastnight but didnt have the right driver set. thank you for the advice!
I'll look for one of those sets but what would you search for if i needed to find it?
Thanks again, I just got a set off of Ebay. Hopefully it'll be here next week
With any luck it'll be a connection issue.
I have had the exact same problem. Because I got the Tytn through work I made our IT department handle the issue and I am currently waiting for a replacement and to find out what happened.
Yep, it looks like the problems the OP is having are very similar to the problems we've been having over in this thread:
http://forum.xda-developers.com/showthread.php?t=291027
I'm beginning to think it's a hardware problem as well but not entirely sure.
People in the above thread mentioned that using the scroll wheel a while then moving back to use the D pad fixed the problem (very briefly in my case.) Once I use the center D pad button again it locks the hardware buttons under the screen until I make my device sleep and resume.
Somtimes rather than making all the front hardware buttons unresponsive the issue is that once I use the Down Dpad button I can't use the up button. Pressing up will make it go down, as will pressing down (at least that's working ).
Regarding the white screen - this sometimes also occurs. I can force it to white screen by putting a little pressure on the silver panel surrounding the top, right and bottom of the screen (I have an imate jasjam). Randomly when there's no pressure on the rim and I wake it out of standby, it has a white screen that can only be fixed by turning the screen off and on again.
Finally, the LED indicator seems screwy. Sometimes it never flashes. Other times it flashes sporadically (uneven intervals - we're talking maybe a minute between one flash then seconds before another). When I charge it sometimes the LED doesn't come on but nevertheless it charges. Sometimes if the LED is on it never turns green to indicate a full charge. Yet other times it comes on orange, turns green, then never switches off!
Is it possible that
a) The hardware button problems.
b) The white screen problem.
c) The LED problem.
are all related to some kind of connection going loose? Why would the hardware button problem be temporarily fixable with use of the scroll wheel if this were the case?
The other thread has fallen silent. I'm hoping that some of the gurus in here can offer some input here, even if they don't know the answer but can formulate an opinion. I know very little about these devices.
Thanks in advance guys!
PS - don't really know if I should start another thread, I've posted here as it seems like very much the same issue.
Anybody any idea? advice?
I had a similar problem with my HERM100. I didn't mess around with it too much, I just had Cingular replace it out of warranty exchange (thank god those original ROMs are on the wiki ). I did notice however that after doing a master reset, the screen would function again although I haven't messed around with it too much. I got so frustrated with removing the battery for 5 minutes and STILL powering on with a white screen that I just threw it in my back seat until the new one arrived.
I don't have these screen issues. I only have hardware button problems. It's so damn frustrating! I already own a replacement.
I just received a call from my girlfriend. I wasn't able to answer the phone with the buttons, only with a screentap. I also wasn't able to close the call with the hardware button. Since the side buttons work, I went to settings -> phone, closed it, and there we go. The hardware buttons worked again.
Why the heck is this? I truly hope for some wizz out there with some advice, since HTC would only tell me to send it back after replacing it with a new TyTN with same issues.
Regards,
DM.
Anyone anyone?
HELP!!!!
barncourt said:
Hi. This sounds very similar to a problem that I experienced with a HERMES100. I bought the phone off someone on Ebay recently - someone had obviously scrambled the radio on it. I re-flashed it, and it sprang to life. However, after a couple of days, I experienced a problem where occasionally the LCD would stop refreshing, all the pixels faded away leaving only a white screen. Under these circumstances, some of the buttons on the phone stopped working. Turning phone on/off sometimes cured the problem, or it would require the occasional hard reset. This would happen once or twice a day and I suspect thats why someone tried to re-flash the phone.
In the end, out of curiosity I took the entire phone apart, put it all back together again and now there are no more problems!! Totally fixed!
My suspicion is that it was one of the ribbon cable push connectors on the mainboard - possibly not seated properly, or a bit of dirt contaminating the connection. Obviously when I took the phone apart I must have re-seated it.
If you are planning to take your phone apart, please exercise considerable care because some of the parts are very small and easily damaged. I would recommend buying a proper kit to take it apart. I bought mine for about £5 off ebay. Particularly useful are the plastic spoon "wedges" used to gently prise open the case after removing the screens. Don't use a screwdriver - you will scratch the case.
Good luck.
Click to expand...
Click to collapse
This is my first post as I've so far managed to cure all my issues from just reading the forum. However, I am now having a similar problem with the white screen.
I have a cingular 8525. It fell and the following day the call and end buttons remained lit and wouldn't turn off and they also wouldn't work.
I soft reset, nothing, I then removed the battery and when I turned it back on, there was a white screen and the buttons below still don't work.
I have read the other posts on this issue, but I need help on exactly what kit to buy to reconnect the screen cable and instructions on how to do it as I've never taken apart a phone before, although I have dabbled with other electronic devices.
Your help would be much appreciated, as I am in Jamaica and there are no technicians here who I trust to help.
Thanks in advance.
Below are links to 2 kits I'm thinking of getting. Is either one better than the other?
http://www.pdasmart.com/pdaphonehtcmini.htm?gclid=CJrHntO-hosCFQx1VAodaQf6KQ
http://cgi.ebay.com/SCREWDRIVERS-TO...01677255QQcategoryZ108648QQrdZ1QQcmdZViewItem
CINGULAR IN JA said:
This is my first post as I've so far managed to cure all my issues from just reading the forum. However, I am now having a similar problem with the white screen.
I have a cingular 8525. It fell and the following day the call and end buttons remained lit and wouldn't turn off and they also wouldn't work.
I soft reset, nothing, I then removed the battery and when I turned it back on, there was a white screen and the buttons below still don't work.
I have read the other posts on this issue, but I need help on exactly what kit to buy to reconnect the screen cable and instructions on how to do it as I've never taken apart a phone before, although I have dabbled with other electronic devices.
Your help would be much appreciated, as I am in Jamaica and there are no technicians here who I trust to help.
Thanks in advance.
Below are links to 2 kits I'm thinking of getting. Is either one better than the other?
http://www.pdasmart.com/pdaphonehtcmini.htm?gclid=CJrHntO-hosCFQx1VAodaQf6KQ
http://cgi.ebay.com/SCREWDRIVERS-TO...01677255QQcategoryZ108648QQrdZ1QQcmdZViewItem
Click to expand...
Click to collapse
Both kits look ok. PDA one tells you a little more but the basics appear to be in both.
I'm curious though you soft reset and took the battery out, but have you done a HARD reset? I would always try this first before dismantling.
Mike
In my case, they also are always lit up when the screen is also active.
And no matter what ROM version, they occasionally stop responding. Side buttons keep working.
mikechannon said:
Both kits look ok. PDA one tells you a little more but the basics appear to be in both.
I'm curious though you soft reset and took the battery out, but have you done a HARD reset? I would always try this first before dismantling.
Mike
Click to expand...
Click to collapse
Thanks for the response.
I couldn't do a hard reset because the buttons weren't working.
I have made some progress with the phone now. Found a tech guy who looked at it for me. The white screen is gone, but the buttons still stop working from time to time.
All the connections seem ok.
Is there anything else that could cause the buttons to malfunction?
CINGULAR IN JA said:
Thanks for the response.
I couldn't do a hard reset because the buttons weren't working.
I have made some progress with the phone now. Found a tech guy who looked at it for me. The white screen is gone, but the buttons still stop working from time to time.
All the connections seem ok.
Is there anything else that could cause the buttons to malfunction?
Click to expand...
Click to collapse
Nothing obvious.
Have you got applications installed that you have loaded - could be one thats playing up.
Have you now been able to do a hard reset?
If taking device apart and reassembling improved things it does suggest hardware though and might be worth double checking all those multi-connector blocks for good connections - i.e. take them out and in a few times to ensure any oxidation on contacts is removed.
Mike
mikechannon said:
Nothing obvious.
Have you got applications installed that you have loaded - could be one thats playing up.
Have you now been able to do a hard reset?
If taking device apart and reassembling improved things it does suggest hardware though and might be worth double checking all those multi-connector blocks for good connections - i.e. take them out and in a few times to ensure any oxidation on contacts is removed.
Mike
Click to expand...
Click to collapse
Thanks Mike.
I will give that a shot.
I haven't installed any new applications recently, so I don't think it is a software issue.
Thanks again.
CINGULAR IN JA said:
Thanks Mike.
I will give that a shot.
I haven't installed any new applications recently, so I don't think it is a software issue.
Thanks again.
Click to expand...
Click to collapse
If it wouldn't be a software issue, why is it, in my case, instantly resolved when going to settings -> phone with the side buttons?
i had this problem i took it to a guy who fixed the problem he said it was a very small tear in the flex cable which causes this white screen every now ant then and the buton problem , sorry to say its the cable problem and u need a very capable person to fix it or replace it with a new one . its very common problem baised on the guy who fixed it .
dmxl said:
I don't have these screen issues. I only have hardware button problems. It's so damn frustrating! I already own a replacement.
I just received a call from my girlfriend. I wasn't able to answer the phone with the buttons, only with a screentap. I also wasn't able to close the call with the hardware button. Since the side buttons work, I went to settings -> phone, closed it, and there we go. The hardware buttons worked again.
Why the heck is this? I truly hope for some wizz out there with some advice, since HTC would only tell me to send it back after replacing it with a new TyTN with same issues.
Regards,
DM.
Click to expand...
Click to collapse
Exactly what is happening to me, no white screen issues, just screen taps and answering calls, I also have another problem where the PDA will not allow me to open anything, be it the start menu or contacts, it will open and quickly close again. I have had mine swapped through Telstra in Sydney, it worked fine for a while and then the same crap again. These problems started before I even touched the OS, so it must be a build problem. Maybe we should write a joint letter to HTC letting them know that there is a serious problem with their machine.
I have had the same problem, got my Tytn through work so we sent it back to the company that supplied it to us. Got it back yesterday and they had replaced the "switchboard". Not sure what it is but there was the problem. Had white screen and buttons not working.
The phone was working fine but my son said the touch screen was working off and on. Now it doesn't come on at all. I am trying to find out if the phone needs a new lcd screen or maybe it's just a cable causing the phone not to work. We tried the reset, took out battery/sim card and still nothing happens on the phone. The screen is still a grayish white. It seems to be charging. When we put the battery back in it vibrates like it wants to turn on. Any help with this problem would be appreciated.
Still bad
Hi, hope you fixed the phone, sounds like a bad flex, you can get a new one from eBay (about 16Dlls).
Changing the flex isn't that difficult but you must be VERY CAREFUL or you can damage some phone internals, there is a service manual but i think you cant watch some disassembly videos on youtube, they're better.
Hi, I cracked my outer screen on my A500 and just got a replacement. The tablet worked fine though. The touch screen still allowed selection of anything on the entire screen even though it had lots of cracks on it. The LCD screen wasn't damaged at all.
Followed the videos to replace the screen that are posted to the letter, slowly and methodically. So I separated the outer screen from the display OK (it was a bit of a challenge since the double sided tape was holding pretty good).
Everything went together OK. I go to start it and the screen glows as it normally does as the very first part of the power-on. But nothing else. No logo, no messages - nothing.
But I plugged it into my PC via micro USB on a whim and lo and behold, I can actually see the internal storage and SD card. Looks like everything is there. And if I do the long press where I recall some of the icons are, I can feel the slight vibration as it selects the icon. So it would also appear that the touch screen is functioning too.
So it looks like the unit boots but for some reason, won't display. The screen just glows faintly like the very first part of a power-on.
Is there hope? Is there something I can do or check? Is there a way to verify the LCD without buying a new one?
Thanks,
Bob
RKramkowski said:
Hi, I cracked my outer screen on my A500 and just got a replacement. The tablet worked fine though. The touch screen still allowed selection of anything on the entire screen even though it had lots of cracks on it. The LCD screen wasn't damaged at all.
Followed the videos to replace the screen that are posted to the letter, slowly and methodically. So I separated the outer screen from the display OK (it was a bit of a challenge since the double sided tape was holding pretty good).
Everything went together OK. I go to start it and the screen glows as it normally does as the very first part of the power-on. But nothing else. No logo, no messages - nothing.
But I plugged it into my PC via micro USB on a whim and lo and behold, I can actually see the internal storage and SD card. Looks like everything is there. And if I do the long press where I recall some of the icons are, I can feel the slight vibration as it selects the icon. So it would also appear that the touch screen is functioning too.
So it looks like the unit boots but for some reason, won't display. The screen just glows faintly like the very first part of a power-on.
Is there hope? Is there something I can do or check? Is there a way to verify the LCD without buying a new one?
Thanks,
Bob
Click to expand...
Click to collapse
Well Bob, glad to see some folks take matters into their own hands!
I can't find the post, as it was a couple years or so ago. But I specifically remember a similar situation. And from what I know, when you tighten/place the screens together, you have to make sure you tighten them evenly, or else nothing works. Something to that effect. Also, I would probably take it apart again, and double check that everything is connected the proper way. Look for possible bent pins and such.
As far as I know, there are no software maintenance apps to check the lcd. Not to my knowledge anyhow, As we pretty much have all maintenance software for the 500/501.
Wish I could be of more help. I know awhile back, a couple of folks here in the forum replaced theirs after their kids stepped on them.
Hi,
i bought a factory refurbished I9600F from aliexpress. It worked great for 3 days, then the phone became slow to respond, the screen was flickering in yellow-green tones, and then wouldn't come back on but stay black. (but I would still get notification sounds for incoming messages, the notification LED was still working, and the menu keys also light up when I press home/power).
Pulling the battery fixed the issue once, but the problem came back after 1 hour.
I managed to revive the phone once more by pulling the battery and holding the power button to drain all remaining power in the device. The phone was working again for a few hours, but now it's back to having a black screen and even the power drain method doesn't work anymore...
So i'm guessing that replacing the screen won't fix the issue, since the screen is working just fine for a a while (both image and touch are perfect) - but then somehow there must be some electrical issue that causes the graphics unit to malfunction.
I checked the easily accessible connector to the left side of the battery, but it seems that the screen is mainly connected via flex cables that cannot be accessed unless you heat up your device and pry out the screen.
I have found some information on the internet that pressing hard on the spot where the flex cable connector is might fix the problem, but this didn't work for me.
FYI, I'm running the default Samsung firmware the device shipped with and used Kies + OTA update to get the latest official FW. No rooting or any other mods. Just some regular apps installed.
Any recommendation what I could try to fix this problem? Thank you all!!!
BTW, I have found similar reports on the internet here:
http://forums.androidcentral.com/samsung-galaxy-s5/405238-galaxy-s5-static-screen-won-t-turn.html
But the linked how-to-fix guide states that heating up the display assembly is only recommended on devices with a broken screen... So now I don't want to risk breaking my working screen.
So mainly my options are
a) open the device to check the flex cable connection
b) buy a new battery to see if that solves if (some people have reported success with a different battery)
c) buy a new screen assembly on aliexpress for around €135 and hope that a new screen will fix it...
Thoughts?
wutzin said:
So mainly my options are
a) open the device to check the flex cable connection
b) buy a new battery to see if that solves if (some people have reported success with a different battery)
c) buy a new screen assembly on aliexpress for around €135 and hope that a new screen will fix it...
Thoughts?
Click to expand...
Click to collapse
Hello, how did you solve this? I currently have the same problem.
gustav9797 said:
Hello, how did you solve this? I currently have the same problem.
Click to expand...
Click to collapse
sorry, i actually never was able to get this resolved. I tried removing the screen to get to the flex cable, but broke the screen because I hadn't heated up the glue enough...
Had to buy another device.
Sorry I don't have better news...
wutzin said:
sorry, i actually never was able to get this resolved. I tried removing the screen to get to the flex cable, but broke the screen because I hadn't heated up the glue enough...
Had to buy another device.
Sorry I don't have better news...
Click to expand...
Click to collapse
I'm going find out the cause for this issue. I've disassembled one device that only lights up when it is warm. If I put it in the cooler it refuses to light up for some time after that. I tried placing only the screen in the cooler, also only the phone body in the cooler, but couldn't find any difference doing this as it refuses to light up both times for a couple of minutes then it works great again.
I've ordered another device that had its screen shattered so I will try my current screen on that device.
It could be some internal hardware fault in the mobo, it could be the LCD connector having a bad connection somehow, it could be the screen assembly itself, but I will find out eventually.
I've seen many places on the internet where people say this is a software issue. There is a very simple answer to that question. How could it be a software issue if not even the boot logo shows up when you start the phone?
I will keep this thread updated.
Verified that this is a problem with the motherboard. What circuit on the motherboard could have problems with cold temperatures? The main power one? If so, I will try replacing it with a different one.
Update: Was not able to fix it. Motherboard is now scrap.
Hey guys,
I recently changed the battery on my A2017G, I was very careful not to damage anything and to dismount everything properly.
After putting the phone back together, somehow it didn't want to boot anymore (bootstack screen, and then blinking red led with everything except fastboot).
I figured it was a software issue, since it got solved with a full EDL flash. I still don't know how a battery change could have messed that up.
But now, the right capacitive button (recent apps) doesn't react at all anymore. The home and previous buttons still work perfectly.
I flashed other EDL roms, did a full factory reset, or tried swapping buttons, nothing changes, still the right one isn't reacting.
I carefully checked all the flex cables and connectors inside the phone, they all seem as good as new, no scratch, bend or any other damage.
So my question is, could it be a software issue? Since the EDL full flash is not always doing things correctly...
If it's a hardware issue, I guess I could have messed up the screen flex cable without leaving a mark on it.
But wouldn't that prevent all the buttons to work?
I just want to be sure, before buying a new screen frame (those aren't cheap).
Thanks
Stremon said:
Hey guys,
I recently changed the battery on my A2017G, I was very careful not to damage anything and to dismount everything properly.
After putting the phone back together, somehow it didn't want to boot anymore (bootstack screen, and then blinking red led with everything except fastboot).
I figured it was a software issue, since it got solved with a full EDL flash. I still don't know how a battery change could have messed that up.
But now, the right capacitive button (recent apps) doesn't react at all anymore. The home and previous buttons still work perfectly.
I flashed other EDL roms, did a full factory reset, or tried swapping buttons, nothing changes, still the right one isn't reacting.
I carefully checked all the flex cables and connectors inside the phone, they all seem as good as new, no scratch, bend or any other damage.
So my question is, could it be a software issue? Since the EDL full flash is not always doing things correctly...
If it's a hardware issue, I guess I could have messed up the screen flex cable without leaving a mark on it.
But wouldn't that prevent all the buttons to work?
I just want to be sure, before buying a new screen frame (those aren't cheap).
Thanks
Click to expand...
Click to collapse
You would need to buy a new screen (i.e. around $90) so I say you should start looking into gesture navigation or at least on-screen navbar if nothing works out... the capacitive sensors are affixed to the screen.
I usually had my Back button crap out, but weirdly enough it would start working either after doing a lot of pressure on it or after a reboot.
The capacitive button surely comes through the screen connector, did you check that?
Choose an username... said:
You would need to buy a new screen (i.e. around $90) so I say you should start looking into gesture navigation or at least on-screen navbar if nothing works out... the capacitive sensors are affixed to the screen.
I usually had my Back button crap out, but weirdly enough it would start working either after doing a lot of pressure on it or after a reboot.
The capacitive button surely comes through the screen connector, did you check that?
Click to expand...
Click to collapse
Yes I did, it seems in perfect state.
My theory is that I might have accidentally put some pressure on this flex connector with my plastic tool, while trying to remove the battery.
There are no visible damages, but maybe it's just damaged inside.
Right now I'm using the MiPop, but it's less than ideal...
I wish there was a way to put the on screen softkeys back and disable de hardware ones.
Probably enabling the softkeys isn't that hard, but disabling the hardware ones... ?
Stremon said:
Yes I did, it seems in perfect state.
My theory is that I might have accidentally put some pressure on this flex connector with my plastic tool, while trying to remove the battery.
There are no visible damages, but maybe it's just damaged inside.
Right now I'm using the MiPop, but it's less than ideal...
I wish there was a way to put the on screen softkeys back and disable de hardware ones.
Probably enabling the softkeys isn't that hard, but disabling the hardware ones... ?
Click to expand...
Click to collapse
Try Fluid Navigation Gestures, I'm currently on another phone with navbar and i'm using that. it's very nice and doesn't use screen space
To enable the navbar you should be on a custom ROM or at least on Chinese MiFavor, I'm not sure if it's possible on G/U systems and I recall not being able to enable the navbar on these
actually I just found that:
https://forum.xda-developers.com/axon-7/themes/a2017g-navigation-bar-enabler-disabler-t3740817
since I'm also using raystef66's custom rom, I guess it's perfect