Database Users

[Q] nexus 10 Bootloop - CWM exits in 30 secs or so `

Hi,
I recently got a nexus 10, and started working on rooting. I have unlocked it, installed CWM recovery and booted it twice. I have not rooted it yet. Now I realized, that everytime I entered the CWM recovery mode, it automatically reboots back into recovery or normal boot in about 30 seconds or so. (this is not the main problem!)
But one booting up second time, I got a notification of sytem update for 4.2 jellybean (please note initially the device was on 4.2 JB JVP15P), I clicked on install, it booted into CWM recovery, but then it failed to continue with installation, as it complained about authentication failure for the zip fle or something of that sort. So I chose to boot the device without installing the update, now it entered a boot loop. I have tried erasing cache and userdata (both using fastboot commandline, and options in the CWM - in the 30 secs I get). It did not work.
After trying it for a few times, I tried restoring some backups I had made. Initially it complained about MD5 mismatch, and then later on it complained about unable to mount cache/* and unable to mount sdcard.
I have read around and the universal solution seems to be to restore stock images. Is that the solution for me as well?
Any help would be greatly appreciated, and I am noob in this area, so pardon me if I act like one.
cheers,
brickin

I'd like to know part of the answer to this as well. The tab is running fine and TWRP works fine, but CWM constantly reboots and I have the same mounting problems within both CWM and TWRP. I've tried flashing stock image and recovery but it's made no difference.

IIRC, the newest CWM has an issue with devices that allow multiple users (aka: N7 and N10). Flash TWRP and don't look back.
Sent from my Galaxy Nexus using Tapatalk 2
---------- Post added at 06:07 AM ---------- Previous post was at 06:05 AM ----------
Also, TWRP supports USB OTG while CWM doesn't.
Sent from my Galaxy Nexus using Tapatalk 2

I was having a similar issue with cwm. This explains everything.

Blueback22 said:
IIRC, the newest CWM has an issue with devices that allow multiple users (aka: N7 and N10). Flash TWRP and don't look back.
Sent from my Galaxy Nexus using Tapatalk 2
---------- Post added at 06:07 AM ---------- Previous post was at 06:05 AM ----------
Also, TWRP supports USB OTG while CWM doesn't.
Sent from my Galaxy Nexus using Tapatalk 2
Click to expand...
Click to collapse
Hi Blueback22,
Thanks a lot for your reply.
Would flashing TWRP solve everything? And also is it ok to flash TWRP now, would it be able to restore the backups I have made using CWM?
Do I need to uninstall or remove the CWM recovery image that has alreday been flashed? or will TWRP image overwrite it?
How do I solve the bootloop issue?
I am unable to get a stock image for JB version: JVP15P. Do you know where I can find the factory image for that?
OR is it ok for me to flash the JOP40C image? Would it cause any problems - (like would it cry saying checksum mismatch or something like that)?
Also, what is the solution for unable to mount sdcard problem?
Sorry for asking so many questions, but I do not wish to brick my device, hence I wish to understand what I am going to do, and ensure that it is not going to harm my device.
Your replies to this post is and will be deeply appreciated.
Thanks,
brickin

brickin said:
Hi Blueback22,
Thanks a lot for your reply.
Would flashing TWRP solve everything? And also is it ok to flash TWRP now, would it be able to restore the backups I have made using CWM?
Do I need to uninstall or remove the CWM recovery image that has alreday been flashed? or will TWRP image overwrite it?
How do I solve the bootloop issue?
I am unable to get a stock image for JB version: JVP15P. Do you know where I can find the factory image for that?
OR is it ok for me to flash the JOP40C image? Would it cause any problems - (like would it cry saying checksum mismatch or something like that)?
Also, what is the solution for unable to mount sdcard problem?
Sorry for asking so many questions, but I do not wish to brick my device, hence I wish to understand what I am going to do, and ensure that it is not going to harm my device.
Your replies to this post is and will be deeply appreciated.
Thanks,
brickin
Click to expand...
Click to collapse
If I were you, I would use WugFresh's toolkit to flash back to stock. Then I'd flash TWRP and start from scratch.
I don't know if TWRP will fix your issue all together, but I do remember hearing that there's an issue with CWM on the N10 right now.
Your CWM backups won't work on TWRP IIRC.
Here is where you can get stock images:
https://developers.google.com/android/nexus/images
Sent from my Galaxy Nexus using Tapatalk 2

Hi Blueback22,
Thanks for the help. I was able to fix the problem.
Here are the questions I had and the answers I found, please correct me if I am wrong.
1. My JB version is JVP15P, is it ok to flash JOP40C stock recovery image?
ans: yes
2. Does TWRP work perfectly with nexus 10?
ans: Atleast in my case it did, I was able to root my device, and was also able to take backups.
3. a. CWM complains E: Can't mound /sdcard !
b. CWM Keeps restarting within 30 secs or so !
c. My device is stuck in bootloop !
ans: First, try to wipe your cache, and userdata and reboot. If it does not solve, then flash stock factory image for your device and flash TWRP recovery image.
4. CWM complains E: can't mount /cache/*
ans: Wipe your cache, userdata and reboot.
Reiterating blueback22's point:
DO NOT USE CWM WITH NEXUS 10. USE TWRP INSTEAD.
Cheers,
brickin

BRICKED: OLd bootloader version wont update
C:\android-sdk\platform-tools>fastboot flash bootloader bootloader-manta-mantalj12.img
sending 'bootloader' (1280 KB)...
OKAY [ 0.168s]
writing 'bootloader'...
OKAY [ 0.143s]
finished. total time: 0.318s
C:\android-sdk\platform-tools>fastboot reboot-bootloader
rebooting into bootloader...
OKAY [ 0.006s]
finished. total time: 0.009s
C:\android-sdk\platform-tools>fastboot flash bootloader bootloader-manta-mantalj12.img
sending 'bootloader' (1280 KB)...
OKAY [ 0.170s]
writing 'bootloader'...
OKAY [ 0.145s]
finished. total time: 0.323s
C:\android-sdk\platform-tools>fastboot -w update image-mantaray-jop40c.zip
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
--------------------------------------------
Bootloader Version...: MANTALJ09
Baseband Version.....: no modem
Serial Number........:
--------------------------------------------
checking product...
OKAY [ 0.002s]
checking version-bootloader...
FAILED
Device version-bootloader is 'MANTALJ09'.
Update requires 'MANTALJ12'.
finished. total time: 0.063s
I tried one click root and wug's root kits, but there wasn't any luck in returning to stock and stuck in older bootloader without the possibility of returning to stock. I am stuck in Clockworkmod v6.0.1.9 loops. Tried to search the forum but I couldnt find anything.

ginsboon said:
C:\android-sdk\platform-tools>fastboot flash bootloader bootloader-manta-mantalj12.img
sending 'bootloader' (1280 KB)...
OKAY [ 0.168s]
writing 'bootloader'...
OKAY [ 0.143s]
finished. total time: 0.318s
C:\android-sdk\platform-tools>fastboot reboot-bootloader
rebooting into bootloader...
OKAY [ 0.006s]
finished. total time: 0.009s
C:\android-sdk\platform-tools>fastboot flash bootloader bootloader-manta-mantalj12.img
sending 'bootloader' (1280 KB)...
OKAY [ 0.170s]
writing 'bootloader'...
OKAY [ 0.145s]
finished. total time: 0.323s
C:\android-sdk\platform-tools>fastboot -w update image-mantaray-jop40c.zip
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
--------------------------------------------
Bootloader Version...: MANTALJ09
Baseband Version.....: no modem
Serial Number........:
--------------------------------------------
checking product...
OKAY [ 0.002s]
checking version-bootloader...
FAILED
Device version-bootloader is 'MANTALJ09'.
Update requires 'MANTALJ12'.
finished. total time: 0.063s
I tried one click root and wug's root kits, but there wasn't any luck in returning to stock and stuck in older bootloader without the possibility of returning to stock. I am stuck in Clockworkmod v6.0.1.9 loops. Tried to search the forum but I couldnt find anything.
Click to expand...
Click to collapse
Can you get into the boot loader and flash TWRP to see if that fixes it?
Sent from my Galaxy Nexus using Tapatalk 2

ginsboon said:
returning to stock. I am stuck in Clockworkmod v6.0.1.9 loops. Tried to search the forum but I couldnt find anything.
Click to expand...
Click to collapse
Why don't you try cwm 6.0.2.3? I also loaded 6.0.1.9 and it would reboot in about 30sec time. After going to the latest, cwm has been stable. No more random reboots.
Link to download the latest version...
http://www.clockworkmod.com/rommanager

cowabunga said:
Why don't you try cwm 6.0.2.3? I also loaded 6.0.1.9 and it would reboot in about 30sec time.
I tried to flash cwm 6.0.2.3 and twrp but failed. Still searching for some clues.
Click to expand...
Click to collapse

For OP and other N10 users with stock 4.2 JB Build JVP15P experience:
Is it possible to use the available toolkits (Wug's or mskip's) to unlock the bootloader and root a N10 with the configuration above? Both toolkits ask for Build JOP40C. I've searched the developer forum for this build and found nothing. Thanks!

[Q] Nexus 7 2012 reboots

My Nexus 7 16GB 2012 has started to randomly reboot, it's running 4.4.2 and has been fine for months. This morning I switched it in, turned off the Airplane Mode and after 30 seconds or so it locked up, then reset. This happens every time I turn off Airplane Mode and switch on WiFi.
I'm wondering if there is some sort of corrupt RAM causing the issue? I've tried to do a Factory Reset, but this also fails and I end up back at square one. So I tried Nexus Root Tookit to go back to stock (all I've done previously is unlock the bootloader, no root). This also fails:
sending 'bootloader' (3911 KB)...
OKAY [ 0.516s]
writing 'bootloader'...
FAILED (remote: (InvalidState))
finished. total time: 0.745s
Any suggestions on what to try next?
This may of course be a hardware fault, the device was bought in Summer 2012 on release.

Hi, you need download image of 4.4 and flash it, because 4.4.2 image has corrupt bootloader. If not work try 4.2.2 image and update to kitkat OTA
Cheers, E11

estape11 said:
Hi, you need download image of 4.4 and flash it, because 4.4.2 image has corrupt bootloader. If not work try 4.2.2 image and update to kitkat OTA
Cheers, E11
Click to expand...
Click to collapse
Thanks for the tip, I'll give that a try.
I have been able to use the Nexus Toolkit to temporarily flash the TWRP. I test my hypothesis about an invalid file system and that fails:
/data/media/0/TWRP errno=30
Anyway, it's downloading the image now so lets see if that fixes the problem.

nigelw said:
Thanks for the tip, I'll give that a try.
I have been able to use the Nexus Toolkit to temporarily flash the TWRP. I test my hypothesis about an invalid file system and that fails:
/data/media/0/TWRP errno=30
Anyway, it's downloading the image now so lets see if that fixes the problem.
Click to expand...
Click to collapse
I'm trying KRT16S and the "Back to Stock" option. The Nexus goes to bootloader mode (so I have Android on back with open door). The flashstock.bat runs in a command tool and displays no errors, but nothing appears on the Nexus 7? The script completes, Nexus reboots and is in exactly the same state.
It doesn't seem to want to accept any kind of update.

nigelw said:
I'm trying KRT16S and the "Back to Stock" option. The Nexus goes to bootloader mode (so I have Android on back with open door). The flashstock.bat runs in a command tool and displays no errors, but nothing appears on the Nexus 7? The script completes, Nexus reboots and is in exactly the same state.
It doesn't seem to want to accept any kind of update.
Click to expand...
Click to collapse
Mmm try enter in recovery and do factory reset, if doesnt work, try image of 4.2.2 I'm sure that works
PD. And use Nexus toolkit
Enviado desde mi Xperia P mediante Tapatalk

lagoskon said:
Give a try with twrp 2.6.3.0.
Latest has issues with backups
Στάλθηκε από το Nexus 7 μου χρησιμοποιώντας Tapatalk 2
Click to expand...
Click to collapse
From TWRP I'm able to Wipe and do Factory Reset. It says successful, but when I restart nothing has changed, still got 4.4.2 installed.
I also tried Back to stock with 4.2.2 JDQ39, device goes to Bootloader mode but fails with this error:
sending 'bootloader' (2096 KB)...
OKAY [ 0.287s]
writing 'bootloader'...
FAILED (remote: ()
finished. total time: 0.873s
rebooting into bootloader...
FAILED (command write failed (Unknown error))
finished. total time: 0.637s
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
--------------------------------------------
getvar:version-bootloader FAILED (command write failed (No such device or address))
finished. total time: 0.000s

[Q] [Solved]stuck on: sending 'bootloader' cant flash anything?

Hey there,
I tried to upgrade my Nexus 7 grouper using the 4.23 bootloader and some of the stock roms, cyanogenmod and miui as well as slimkat roms, it kinda didnt work out the way I wanted it to, now I am stuck on: sending 'bootloader' (2100 KB) while not having any recovery nor anything else on my nexus...
the bootloader seems broken, because it always doesnt response when I try to flash an img file..
Thankful for any help

Can you get into fastboot mode?
Did you get the bootloader-grouper-4.23.img file from one of the factory images here?
What is the md5?
I've been reading that these factory image bootloaders (JWR66Y & KOT49H) do not work.
Check out these threads:
http://forum.xda-developers.com/showthread.php?t=1907796
http://forum.xda-developers.com/showthread.php?p=45043044#post45043044

It seems like I used the bootloader from nakasi-kot49h-factory-5e9db5e1
it has got the md5 hash 797a8ddfe19bfe4c485f8a8c119f1bdd
I tried to flash the 4.23 bootloader from the second link, which is the JWR66V version, but still cannot flash it, because by device freezes and the "Flashing bootloader-grouper-4.23.img" of Nexus Root Toolkit doesnt do anything than being stuck.
edit:
Ok , I managed to get my recovery back via fastboot.exe via "fastboot flash recovery recoveryname.img"

I managed to flash normal custom roms via fastboot and adb sideload, but I cannot change the bootloader from the bricked 4.23 one to the one mentioned in the topics which should be a working one from the nexus 7 JWR66V build.
I always get the error
Code:
sending 'bootloader' (2100 KB).
OKAY [ 0.333s]
writing 'bootloader'...
FAILED (remote: (InvalidState))
Any ideas?

The Unified Android Toolkit seems to overwrite the broken bootloader easily and after a few attempts of trying to write the factory image with the Unified Android Toolkit and trying out different usb slots, because I often got the error "Unknown Device" and thus Windows 7 could not install any drivers, it worked out.
Thanks

Can't Flash TWRP

Hello. I am on 6.0.1 MMB29M trying to flash TWRP. I get this error message while doing this.
c:\angler>fastboot flash bootloader twrp-2.8.7.2-angler.img
target reported max download size of 494927872 bytes
sending 'bootloader' (16880 KB)...
OKAY [ 0.392s]
writing 'bootloader'...
FAILED (remote: partition table doesn't exist)
finished. total time: 0.414s
Bootloader is unlocked as well as debugging. I have followed a lot of different guides but can't get passed this error. I had TWRP working on MDB08K but the camera was not working for some strange reason. If anyone can help me get TWRP on MMB29M, that would be great.

bauwoo said:
Hello. I am on 6.0.1 MMB29M trying to flash TWRP. I get this error message while doing this.
c:\angler>fastboot flash bootloader twrp-2.8.7.2-angler.img
target reported max download size of 494927872 bytes
sending 'bootloader' (16880 KB)...
OKAY [ 0.392s]
writing 'bootloader'...
FAILED (remote: partition table doesn't exist)
finished. total time: 0.414s
Bootloader is unlocked as well as debugging. I have followed a lot of different guides but can't get passed this error. I had TWRP working on MDB08K but the camera was not working for some strange reason. If anyone can help me get TWRP on MMB29M, that would be great.
Click to expand...
Click to collapse
Your command is wrong, The command to use is: fastboot flash recovery twrp.the name of your file.img

Just like @jawmail said, you're flashing twrp on the bootloader """slot""
-fastboot flash recovery ***TWPR***.img
-fastboot reboot-bootloader
When your phone reboots, using your volume keys, search for "recovery" and using the power button, confirm it.
PROFIT

bauwoo said:
Hello. I am on 6.0.1 MMB29M trying to flash TWRP. I get this error message while doing this.
c:\angler>fastboot flash bootloader twrp-2.8.7.2-angler.img
target reported max download size of 494927872 bytes
sending 'bootloader' (16880 KB)...
OKAY [ 0.392s]
writing 'bootloader'...
FAILED (remote: partition table doesn't exist)
finished. total time: 0.414s
Bootloader is unlocked as well as debugging. I have followed a lot of different guides but can't get passed this error. I had TWRP working on MDB08K but the camera was not working for some strange reason. If anyone can help me get TWRP on MMB29M, that would be great.
Click to expand...
Click to collapse
Whoa! Does your phone still boot to the bootloader? If so, you're extremely lucky. Flashing a non-bootloader image to the bootloader is pretty much the only way to hard brick a Nexus. You need to take much greater care when doing these things.

Haha. Thanks. Yeah I am really lucky. My phone is working now thanks. Just coming from the S6 Edge. Very different rooting method from that, so yeah I should be way more careful. Thanks for the awesome guide, btw Heisenberg. Running PureNexus with ExperimentalX kernel. Such an amazing combo.
Heisenberg said:
Whoa! Does your phone still boot to the bootloader? If so, you're extremely lucky. Flashing a non-bootloader image to the bootloader is pretty much the only way to hard brick a Nexus. You need to take much greater care when doing these things.
Click to expand...
Click to collapse

Update: nvm, figured it out myself.
I have a similar problem. I flashed the TWRP recovery and it booted into it. Made a nandroid and an EFS backup. Copied the backups to my PC. Wanted to flash the systemless root zip. Issued adb reboot recovery and I get the little Android on his back and saying "no command". Tried flashing recovery again, got this:
sending 'recovery' (16880 KB)...
OKAY [ 0.515s]
writing 'recovery'...
OKAY [ 0.238s]
finished. total time: 0.756s.
And still, I can't boot into twrp by either method. Getting the "no command".
What gives?

Puck24 said:
Update: nvm, figured it out myself.
I have a similar problem. I flashed the TWRP recovery and it booted into it. Made a nandroid and an EFS backup. Copied the backups to my PC. Wanted to flash the systemless root zip. Issued adb reboot recovery and I get the little Android on his back and saying "no command". Tried flashing recovery again, got this:
sending 'recovery' (16880 KB)...
OKAY [ 0.515s]
writing 'recovery'...
OKAY [ 0.238s]
finished. total time: 0.756s.
And still, I can't boot into twrp by either method. Getting the "no command".
What gives?
Click to expand...
Click to collapse
Please explain how you fixed your problem so the info is there for folks in future.
Sent from my Nexus 6P

Heisenberg said:
Please explain how you fixed your problem so the info is there for folks in future.
Sent from my Nexus 6P
Click to expand...
Click to collapse
guess it's a corrupted file?

Actually, I just tried flashing it one more time, rebooted to the bootloader with the phone, not with the command. Then I also used the phone to enter into recovery, not by issuing commands. And it works
Sent from my Nexus 6P using XDA Free mobile app

[HELP] Bricked phone while trying to install custom rom

I was trying to install the AOSiP rom and when I I was doing the twrp installation:
fastboot flash boot twrp-mata_11.img
the error pops out:
target reported max download size of 536870912 bytes
sending 'boot_a' (45048 KB)...
OKAY [ 1.196s]
writing 'boot_a'...
FAILED (remote: Error flashing partition.)
finished. total time: 1.856s
I don't see same errors over the XDA forum. can someone help me?
p.s. screen now is showing fastboot mode
device state - unlocked

Did you unlock critical?
Sent from my ONEPLUS 3T using Tapatalk

seabro01 said:
Did you unlock critical?
Sent from my ONEPLUS 3T using Tapatalk
Click to expand...
Click to collapse
uhh no I did not see that in the tutorial.
I tried: ./fastboot flashing unlock_critical
and looks like it freezes after that command...

ytlei said:
I was trying to install the AOSiP rom and when I I was doing the twrp installation:
fastboot flash boot twrp-mata_11.img
the error pops out:
target reported max download size of 536870912 bytes
sending 'boot_a' (45048 KB)...
OKAY [ 1.196s]
writing 'boot_a'...
FAILED (remote: Error flashing partition.)
finished. total time: 1.856s
I don't see same errors over the XDA forum. can someone help me?
p.s. screen now is showing fastboot mode
device state - unlocked
Click to expand...
Click to collapse
are you rooted?
have you tried downloading the file again?
and if you can still go to bootloader your phone is not bricked, just download stock boot from essential and flash it

yenkoPR said:
are you rooted?
have you tried downloading the file again?
and if you can still go to bootloader your phone is not bricked, just download stock boot from essential and flash it
Click to expand...
Click to collapse
no not rooted
now im trying to flash back to stock, but when I run flash-all.sh error keeps popping up:
remote: Error flashing partition.
FAILED (remote: Error flashing partition.)
finished. total time: 2.025s
target reported max download size of 536870912 bytes
sending 'boot_b' (65536 KB)...
OKAY [ 1.735s]
writing 'boot_b'...
FAILED (remote: Error flashing partition.)
finished. total time: 1.782s
target reported max download size of 536870912 bytes
sending 'cmnlib_a' (512 KB)...
OKAY [ 0.103s]
writing 'cmnlib_a'...
FAILED (remote: Error flashing partition.)
finished. total time: 0.169s
target reported max download size of 536870912 bytes
sending 'cmnlib_b' (512 KB)...
OKAY [ 0.101s]
writing 'cmnlib_b'...
FAILED (remote: Error flashing partition.)
finished. total time: 0.188s
...

Dang now its totally bricked after the flashing failure... cannot boot up. what should I do? send it back to Essential?

What do you mean by can't boot up? Do you see boot animation and have you tried to go back to fast boot or recovery?
Sent from my ONEPLUS 3T using Tapatalk

Try different USB ports and cables. When 8.1 came out I had to swap my cable and change the port I was using on my desktop, for some reason the cable I had been using and the port I had been using since I got the phone was no longer adequate. There were a number of other people having the same issue. Some commands would look to complete properly, but following up with the same command (something un-damaging like fastboot --set-active=a | fastboot --set-active=b) would either error again or show that the 'completed' command hadn't actually done anything. I switched cables/ports around (ended up with an Antek USB-A to USB-C cable in a USB3.1 port) and everything worked properly.
If you're trying to flash a stock build image from Essential, you will probably need critical unlocked because those images do contain a bootloader that gets flashed, and that is secured behind critical.

ytlei said:
Dang now its totally bricked after the flashing failure... cannot boot up. what should I do? send it back to Essential?
Click to expand...
Click to collapse
What cable are you using?
Do not use the cable that came with the phone!!!!!

We are screwed mate, I am on the same boat with you. Essential took no responsibility and offered a 200$ replacement device. The phone doesn't power on anymore and no light indicators are working, so hard bricked.

I had a Asoip screw up(did not disable password) and was only able to get fastboot. Had to see what slot was active and flashed to that slot that was active boot.img,twrp,Asoip and was back up and running. My bootloader was unlocked. I read through all the posts and peoples screw ups and was able to get it up and running again in a day. I never posted as I wanted to learn it on my own. Good luck.........

ytlei said:
I was trying to install the AOSiP rom and when I I was doing the twrp installation:
fastboot flash boot twrp-mata_11.img
the error pops out:
target reported max download size of 536870912 bytes
sending 'boot_a' (45048 KB)...
OKAY [ 1.196s]
writing 'boot_a'...
FAILED (remote: Error flashing partition.)
finished. total time: 1.856s
I don't see same errors over the XDA forum. can someone help me?
p.s. screen now is showing fastboot mode
device state - unlocked
Click to expand...
Click to collapse
What cable did you use while connecting to your computer?
And what is the status now? Are you able to turn it on at all by volume and power key combination?

same here. The phone doesn't power on anymore. btw I used the usb-c TDB cable came with my MacBook pro.
I sent email to essential and they say they can't help me since I tried to flash custom rom...

ytlei said:
same here. The phone doesn't power on anymore. btw I used the usb-c TDB cable came with my MacBook pro.
I sent email to essential and they say they can't help me since I tried to flash custom rom...
Click to expand...
Click to collapse
and pressing the volume down key + power key at the same time doesn't work?.. what happens when you plug your phone into the charger? does it vibrate?

ive had fastboot command problems previously myself with this device and found that the usb port can play a pretty large factor. Swapping usb ports and reattempting to run the commands (as others recommended may be useful) make sure you are using latest version of adb/fastboot and have up to date drivers installed for the phone.
Look at the rooting tutorial there is information in there about swapping active slots (the essential has both a and b paritions) if you set the other slot as the active slot you may be able to regain some communication within fastboot (i would suggest you verify with fastboot devices prior to attempting to flash to partitions).
Additionally you should be able to still recover back to stock without custom recovery using the default recovery partition. I would think that if you are able to access the bootloader you should be able to access the default essential recovery partition. If you can access the standard recovery you should be able to factory reset the phone and sideload a new rom (id suggest the default factory image from essential until you can get back to square one)

I'm in the same boat. Tried to flash twrp after upgrading to 8.1 and got the same Error flashing partition, and now I'm stuck on the bootloader.
I've found that if I lock/unlock and lock/unlock critical it will let me flash the stock 8.1 boot and every other partition except for system and vendor, but gives a flash write error for those. I'm still unable to get past the bootloader.
Essential basically said I'm SOL. $200 out of warranty replacement assuming I live in the US, which I don't.

Mine was doing this too, but it was only a few days old so I returned it. I'm pretty sure it's defective flash memory.

My phone was doing this exact thing. Botched factory installs rendered my phone hardbricked.
Tried a thousand+ things to get it to turn on to no avail. LUCKILY I bought it second hand and have no warranty D:
I want to cry