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[Q] OnePlus One - Unable to unlock bootloader again after relocking

Hi Guys,
Hope to get some help here.
So i unlocked the bootloader of my one plus one and installed supersu + Twrp recovery. All worked fine until i decided to relock the bootloader.
I've put the device into fastboot mode and executed "fastboot oem lock" with twrp recovery still in there.
Now i am trying to unlock the bootloader again using "fastboot oem unlock" to be able to flash the stock recovery and having issues.
output of commands:
Code:
C:\Program Files (x86)\Minimal ADB and Fastboot>fastboot oem unlock
...
OKAY [ 0.004s]
finished. total time: 0.005s
C:\Program Files (x86)\Minimal ADB and Fastboot>
After this it boots straight to twrp recovery. I then hit reboot system and go back to fastboot mode and run the below:
Code:
C:\Program Files (x86)\Minimal ADB and Fastboot>fastboot flash recovery recovery
.img
target reported max download size of 536870912 bytes
sending 'recovery' (12260 KB)...
OKAY [ 0.389s]
writing 'recovery'...
FAILED (remote: Device not unlocked cannot flash or erase)
finished. total time: 0.404s
Anyone has an idea how i can unlock the bootloader again ?
Thanks
Vik

Would it let you reflash the stock factory image thru fastboot? Maybe if you could do that it would let you unlock again. And it would give you stock recovery.
Or else what about the option in developer settings to update the stock cm recovery when installing an update. Maybe you could install an official update thru TWRP and get stock recovery back?
Just throwing out ideas, hope you figure it out

I've documented ths same issue describe here: http://forum.xda-developers.com/oneplus-one/help/locked-bootloader-twr-rooted-t2820341
The solution: http://forum.xda-developers.com/oneplus-one/development/mod-reset-unlock-tamper-bit-t2820912
Download and flash that script.

lemonspeakers said:
I've documented ths same issue describe here: http://forum.xda-developers.com/oneplus-one/help/locked-bootloader-twr-rooted-t2820341
The solution: http://forum.xda-developers.com/oneplus-one/development/mod-reset-unlock-tamper-bit-t2820912
Download and flash that script.
Click to expand...
Click to collapse
Thanks i'll give that a try as soon as am home..

YrrchSebor said:
Would it let you reflash the stock factory image thru fastboot? Maybe if you could do that it would let you unlock again. And it would give you stock recovery.
Or else what about the option in developer settings to update the stock cm recovery when installing an update. Maybe you could install an official update thru TWRP and get stock recovery back?
Just throwing out ideas, hope you figure it out
Click to expand...
Click to collapse
Hi YrrchSebor,
Thanks for the reply.. I already tried all that, even using adb sideload and keep getting same error as mentioned above. I'll try the solution lemonspeakers suggested later today and post the outcome.
Thanks

Vikmeister said:
Hi YrrchSebor,
Thanks for the reply.. I already tried all that, even using adb sideload and keep getting same error as mentioned above. I'll try the solution lemonspeakers suggested later today and post the outcome.
Thanks
Click to expand...
Click to collapse
Be careful if you updated your phone to XNPH30O OTA,
!!! Warning !!!
In the NEW OTA CM11S XNPH30O, the bootloader (aboot) img size changed....
We request all not to apply the unlocker scripts on the new bootloader , until we confirm/find the new bit position.
It might brick your phone and corrupt bootloader...
Click to expand...
Click to collapse
It won't work.. do not try it if you updated to XNPH30O using the OTA.

zephiK said:
Be careful if you updated your phone to XNPH30O OTA,
It won't work.. do not try it if you updated to XNPH30O using the OTA.
Click to expand...
Click to collapse
Thanks for letting me know ZephiK i haven't updated to that version yet. I still have XNPH25R. I should all good.

Fantastic.. Thanks a lot guys.. That worked like a treat.. Bootloader is now unlocked.
:laugh::good:

lemonspeakers said:
I've documented ths same issue describe here: http://forum.xda-developers.com/oneplus-one/help/locked-bootloader-twr-rooted-t2820341
The solution: http://forum.xda-developers.com/oneplus-one/development/mod-reset-unlock-tamper-bit-t2820912
Download and flash that script.
Click to expand...
Click to collapse
I ran this command:
Code:
fastboot.exe boot TWRP-2.7.1.0.img
But the next step does not work:
Code:
It will boot your phone into recovery once from the recovery image
stored in your PC temporarily
then you can flash the zip either by sideload or from sdcard...
I got:
downloading 'boot.img'...
OKAY [ 0.484s]
booting...
FAILED (remote: Device not unlocked cannot boot)
finished. total time: 0.487s

That's because you can't boot a recovery with the recent bootloader unless you're unlocked.
Transmitted via Bacon

Hello,
so how to unlock the bootloader when:
- i can only access to fastboot and i have connectivity to pc;
- command 'fastboot oem unlock' doesn't work( FAILED (remote: oem unlock is disabled) )
- command 'fastboot flash recovery firmware.zip' doesn't work (FAILED (remote: Device not unlocked cannot flash or erase))
- all adb commands say: "error: device not found"
- i can't access recovery for use adb sideload (phone freezes with 1+ icon in screen)
- i can't access Android (phone freezes with 1+ icon in screen)
What can i do?
Thanks in advance!
Gustavo

Im have the same issue but I have no recovery installed..Anyway to do this

i have same issue plz give me any solution if you found any???plz let me know plzzzzz
​
piriri007 said:
Hello,
so how to unlock the bootloader when:
- i can only access to fastboot and i have connectivity to pc;
- command 'fastboot oem unlock' doesn't work( FAILED (remote: oem unlock is disabled) )
- command 'fastboot flash recovery firmware.zip' doesn't work (FAILED (remote: Device not unlocked cannot flash or erase))
- all adb commands say: "error: device not found"
- i can't access recovery for use adb sideload (phone freezes with 1+ icon in screen)
- i can't access Android (phone freezes with 1+ icon in screen)
What can i do?
Thanks in advance!
Gustavo
Click to expand...
Click to collapse
plz help same issue

Root: Stuck at "Your device is booting now"

Hello! I tried to root my Honor 6x (BLN-L21, EMUI 5.0) following the instructions there:
cyberkey.in/how-to-root-honor-6x-100-working/
The bootloader was successfully unlocked.
But when I tried to flash TWRP the process failed and now my phone is stuck on boot :
"Your device has been unlocked and can't be trusted [...] Your device is booting now."
I can get access to recovery and fastboot. I wiped the cache and tried a factory reset but nothing changed, my system won't start and I don't know what to do.
Please help!

if you have the boot backup then restore it.

venugopalu007 said:
if you have the boot backup then restore it.
Click to expand...
Click to collapse
I don't have any backup. Is there a way to just reset everything? Also I don't know how to connect to the phone anymore since adb won't find the device.

if you cannot find the boot.img
just do a rollback bro
here is the link
first dload this
http://download-c.huawei.com/download/downloadCenter?downloadId=94070&version=376169&siteCode=de-h
and this now
if your device is BLN-L21C432B151 http://update.hicloud.com:8180/TDS/data/files/p3/s15/G1277/g104/v84712/f1/full/update.zip
or BLN-L21C185B131 http://update.hicloud.com:8180/TDS/data/files/p3/s15/G1277/g104/v75593/f1/full/update.zip

I think that I flashed the wrong files in "boot" and "recovery". Please tell me which files I should flash there.
I used the commands:
.\fastboot flash boot twrp.img
.\fastboot flash recovery twrp.img

Stinks said:
I think that I flashed the wrong files in "boot" and "recovery". Please tell me which files I should flash there.
I used the commands:
.\fastboot flash boot twrp.img
.\fastboot flash recovery twrp.img
Click to expand...
Click to collapse
The guide from "cyberkey.in/how-to-root-honor-6x-100-working/" is simply wrong when it comes to flashing the twrp recovery. If you really followed this guide completely then you flashed the recovery to the boot partition.
Use "fastboot flash recovery twrp.img" to flash the recovery.
You will still have to flash the boot image to your boot partition then (fastboot flash boot boot.img).

Stinks said:
I don't have any backup. Is there a way to just reset everything? Also I don't know how to connect to the phone anymore since adb won't find the device.
Click to expand...
Click to collapse
Use fastboot flash recovery twrpname.img to flash the recovery

Ok so basically I need to flash the boot image. However I don't know where to find the stock boot image. I downloaded the so-called "full version" of the stock firmware that I found here: boycracked.com/2017/07/20/official-huawei-honor-6x-bln-l21-berlin-l21-stock-rom-firmware/
However there was no boot.img file inside.
If you could direct me to the proper stock boot.img or send me one, that would greatly help. I had EMUI 5.0 with Nougat 7.0 I believe, phone version BLN-L21.

V
Stinks said:
Ok so basically I need to flash the boot image. However I don't know where to find the stock boot image. I downloaded the so-called "full version" of the stock firmware that I found here: boycracked.com/2017/07/20/official-huawei-honor-6x-bln-l21-berlin-l21-stock-rom-firmware/
However there was no boot.img file inside.
If you could direct me to the proper stock boot.img or send me one, that would greatly help. I had EMUI 5.0 with Nougat 7.0 I believe, phone version BLN-L21.
Click to expand...
Click to collapse
Bro there is update.app open it with huawei update extractor then you will see the the boot image.but remember the emui 4.1 boot wont help you in emui 5 .the boot.img must be emui 5 once.

venugopalu007 said:
V
Bro there is update.app open it with huawei update extractor then you will see the the boot image.but remember the emui 4.1 boot wont help you in emui 5 .the boot.img must be emui 5 once.
Click to expand...
Click to collapse
Thanks. I successfully updated boot.img and and recovery.img, but system won't load, so I might have imported from the wrong STOCK version.
I tried to reinstall a stock ROM using:
fastboot flash system system.img
But I got this error message:
target reported max download size of 471859200 bytes
sending sparse 'system' (444686 KB)...
OKAY [ 12.901s]
writing 'system'...
FAILED (remote: sparse flash write failure)
finished. total time: 12.929s
Then I tried to erase the system file with "erase system" and got this error:
erasing 'system'...
FAILED (remote: Command not allowed)
finished. total time: 0.013s
I guess that the only option now is to install the files on an external SD card?

Stinks said:
Thanks. I successfully updated boot.img and and recovery.img, but system won't load, so I might have imported from the wrong STOCK version.
I tried to reinstall a stock ROM using:
fastboot flash system system.img
But I got this error message:
target reported max download size of 471859200 bytes
sending sparse 'system' (444686 KB)...
OKAY [ 12.901s]
writing 'system'...
FAILED (remote: sparse flash write failure)
finished. total time: 12.929s
Then I tried to erase the system file with "erase system" and got this error:
erasing 'system'...
FAILED (remote: Command not allowed)
finished. total time: 0.013s
I guess that the only option now is to install the files on an external SD card?
Click to expand...
Click to collapse
Bro y this ,just do a rollback .

Stinks said:
Thanks. I successfully updated boot.img and and recovery.img, but system won't load, so I might have imported from the wrong STOCK version.
I tried to reinstall a stock ROM using:
fastboot flash system system.img
But I got this error message:
target reported max download size of 471859200 bytes
sending sparse 'system' (444686 KB)...
OKAY [ 12.901s]
writing 'system'...
FAILED (remote: sparse flash write failure)
finished. total time: 12.929s
Then I tried to erase the system file with "erase system" and got this error:
erasing 'system'...
FAILED (remote: Command not allowed)
finished. total time: 0.013s
I guess that the only option now is to install the files on an external SD card?
Click to expand...
Click to collapse
I recommend you to download firmware files only from the official honor website or by using the huawei firmware finder(https://forum.xda-developers.com/tools/general/huawei-firmware-finder-team-mt-t3469146)
In this case try to use huawei firmware finder to get the right stock version for your phone. Download these two files: e.g. update.zip & update_full_BLN-L21_hw_eu.zip.
Export the following image files: recovery, system, boot and cust.
The try to flash them:
fastboot flash boot boot.img
fastboot flash system system.img
fastboot flash cust cust.img
fastboot flash recovery recovery.img
If flashing a partition via fastboot fails then it is usually because it's the wrong image or just not made for your phone.

Thank you guys, you saved my phone! I eventually managed to flash the files from Nougat update for European Honor 6X BLN-L21C432B360 that I found there: stechguide.com/honor-6x-b360-nougat-update/
Now the phone is working fine.

Stinks said:
Thank you guys, you saved my phone! I eventually managed to flash the files from Nougat update for European Honor 6X BLN-L21C432B360 that I found there: stechguide.com/honor-6x-b360-nougat-update/
Now the phone is working fine.
Click to expand...
Click to collapse
Glad you revived your phone

question
​
Stinks said:
Hello! I tried to root my Honor 6x (BLN-L21, EMUI 5.0) following the instructions there:
cyberkey.in/how-to-root-honor-6x-100-working/
The bootloader was successfully unlocked.
But when I tried to flash TWRP the process failed and now my phone is stuck on boot :
"Your device has been unlocked and can't be trusted [...] Your device is booting now."
I can get access to recovery and fastboot. I wiped the cache and tried a factory reset but nothing changed, my system won't start and I don't know what to do.
Please help!
Click to expand...
Click to collapse
my phone is stuck at your device is booting now i cant get to any of other functions such as fastboot or recovry i can only acces it after full charge is gone and after charging.how did you get to acces fastboot or recover.

[email protected] said:
question
my phone is stuck at your device is booting now i cant get to any of other functions such as fastboot or recovry i can only acces it after full charge is gone and after charging.how did you get to acces fastboot or recover.
Click to expand...
Click to collapse
did you solve your issue.....I have same problem now

nokiasatyam said:
did you solve your issue.....I have same problem now
Click to expand...
Click to collapse
Hello, could you be more specific about your problem? I'll be able to help you.
Brief Explanation:
From the screen on which you're stuck, press and hold power button for about 10 seconds to forcibly restart your device. when you see the same screen again, immediately press and hold volume up button(for about 3 seconds) to boot to eRecovery.
> Choose shut down option on eRecovery. press and hold vol down button and insert the charging cable to boot to fastboot.
> Press and hold power and volume up button to boot to recovery. (You could do this even from fastboot screen and the screen you're stuck at).

how to flash magisk patched boot.img?

boys please can u write me steps to flash patched boot. img with fastboot? thank you (european model)

Transfer the patched boot image to PC using 'adb pull' from the path showen in Magisk, boot phone into download mode and flash the patched boot image. 'fastboot flash boot patched_boot.img'

flas patched boot image
Slok 00 said:
boys please can u write me steps to flash patched boot. img with fastboot? thank you (european model)
Click to expand...
Click to collapse
If you flash Magisk from your sd-card, the boot.img is automatically patched by magisk.
Root HTC U11+ European model software number 1.10.401.23
To root your HTC U11+ thru twrp use version 3.2.0.0
1. make sure you got Magisk-15.2 on you sd-card
2. boot into TWRP and leave system read only
3.goto install and install Magisk (in my case 15.2) boot.img is automatically patched
4. you will get error, like "can't mount data" (not to worry)
5. after install GO BACK!! DO NOT REBOOT!!
6. format data AND THEN reboot!!
7 You'll have to setup your phone as a new one; finish that and install Magisk_Manager
8 your now rooted!!! check with root checker
Hope this will help you;
Click to expand...
Click to collapse

milesd said:
Transfer the patched boot image to PC using 'adb pull' from the path showen in Magisk, boot phone into download mode and flash the patched boot image. 'fastboot flash boot patched_boot.img'
Click to expand...
Click to collapse
I have unlocked my U11+ via htcdev.com
I have extracted the boot.img from my RUU
I have installed MagiskManager and patched boot.img
I am having problems flashing the patched_boot.img file ..
I boot to download mode and fastboot flash fails .. see below..
Code:
fastboot flash boot patched_boot.img
target reported max download size of 2399200000 bytes
sending 'boot' (37409 KB)...
FAILED (data write failure (Too many links))
finished. total time: 1.006s
E:\Temp
Can anyone help please!!
I am presently on 2Q4DIMG_OCEAN_M_DUGL_O80_SENSE90GP_HTC_India_SEA_1.24.400.2_Radio_8998-002772-1712011153_release_519104_signed_2_4

I boot to download mode and fastboot flash fails .. see below..
Code:
fastboot flash boot patched_boot.img
target reported max download size of 2399200000 bytes
sending 'boot' (37409 KB)...
FAILED (data write failure (Too many links))
finished. total time: 1.006s
E:\Temp
Can anyone help please!!
Click to expand...
Click to collapse
Try to get a newer htc-fastboot

milesd said:
Try to get a newer htc-fastboot
Click to expand...
Click to collapse
I have tried the fastboot bundled with HTC Sync Manager v3.1.88.3 as well as using the fastboot from platform-tools-v27.0.1-windows but no joy
AFIK there are the latest of the HTC one and the SDK one.
Should also point out I cannot flash the twrp recovery image either.. same error
---------- Post added at 10:56 PM ---------- Previous post was at 10:11 PM ----------
Another thing to mention is that I can erase the partitions without problem using fastboot erase but cannot flash any partitions. The only way I can restore the partitions is to reflash the RUU by putting the RUU zip o the SD card.
I wonder if there is an issue having the 128G sd card in the phone. Will try again tomorrow without the SD card inserted.
The CID's are HTC__060.

You are enable oem unlock in developer option?
Test the connectivity using the following command (provided your phone screen is unlocked)
adb devices
--------------------------------------------------------------------------------------------------------------------------
I think you must rename file patch_boot.img to boot.img
cmd: fastboot flash boot boot.img

newyesor said:
You are enable oem unlock in developer option?
Test the connectivity using the following command (provided your phone screen is unlocked)
adb devices
--------------------------------------------------------------------------------------------------------------------------
I think you must rename file patch_boot.img to boot.img
cmd: fastboot flash boot boot.img
Click to expand...
Click to collapse
I am not new to unlocking and rooting HTC phones I have been doing this since the beginning .. I had an original O2 XDA phone
The phone bootloader is unlocked 100% did it via htcdev and the bootloader screen on both phones says unlocked. There is no issue with connectivity either, adb devices shows the connected phone and other adb commands work fine .. as I said I can even fastboot erase partitions, but am unable to flash them...
I am now thinking it might be my drivers as I am using the windows drivers that came with the latest HTC Sync manager. Later today or tomorrow I might try uninstalling them and using the Universal Naked or the Universal ADB drivers..

Sidewindr said:
I am not new to unlocking and rooting HTC phones I have been doing this since the beginning .. I had an original O2 XDA phone
The phone bootloader is unlocked 100% did it via htcdev and the bootloader screen on both phones says unlocked. There is no issue with connectivity either, adb devices shows the connected phone and other adb commands work fine .. as I said I can even fastboot erase partitions, but am unable to flash them...
I am now thinking it might be my drivers as I am using the windows drivers that came with the latest HTC Sync manager. Later today or tomorrow I might try uninstalling them and using the Universal Naked or the Universal ADB drivers..
Click to expand...
Click to collapse
Have you tried flashing with
fastboot flash boot YOUR_DIRECTORY / patched_boot.img
Just an idea....

Yes tried absolute and relative paths.
Sent from my HTC One M8 using Tapatalk

Switch to another usb port and/or try with another usb cable
https://plus.google.com/+ArtemRussakovskii/posts/RwJ28EdYgCb
https://www.youtube.com/watch?v=5Omhpv7oYdc

Problem solved ... Tried it again after reboot and on a different USB port and it worked .. odd ..

Patched

milesd said:
Transfer the patched boot image to PC using 'adb pull' from the path showen in Magisk, boot phone into download mode and flash the patched boot image. 'fastboot flash boot patched_boot.img'
Click to expand...
Click to collapse
HI I would just like to clarify before I try the download mode.
I have been trying to patch the magisk patched_boot.img in bootloader mode on a HTC U11 with no joy.
This is the error I receive
PS E:\HTC\ADB tools with latest twrp.img Use this one 2019\platform-tools> fastboot flash boot magisk_patched.img
target reported max download size of 536870912 bytes
sending 'boot' (37589 KB)...
OKAY [ 0.915s]
writing 'boot'...
FAILED (remote: Not allowed on PRODUCTION device)
finished. total time: 0.924s
Is it safe to patch in the download mode as stated?
Thanks

Htc bootloader unlocked but Not Allowed on Production Device

I am currently running android 9.0 on htc dual sim model. i have unlocked my bootloader but whenever i tried to flash twrp or any other fastboot command after sending it says not allowed on production device.
target reported max download size of 536870912 bytes
sending 'recovery' (46340 KB)...
OKAY [ 1.320s]
writing 'recovery'...
FAILED (remote: Not allowed on PRODUCTION device)
finished. total time: 1.355s
i have tried both commands
fastboot flash recovery
htc_fastboot flash recovery (through different folder heaving related files)
Help me Solve that issue.

hassanulhaq said:
I am currently running android 9.0 on htc dual sim model. i have unlocked my bootloader but whenever i tried to flash twrp or any other fastboot command after sending it says not allowed on production device.
target reported max download size of 536870912 bytes
sending 'recovery' (46340 KB)...
OKAY [ 1.320s]
writing 'recovery'...
FAILED (remote: Not allowed on PRODUCTION device)
finished. total time: 1.355s
i have tried both commands
fastboot flash recovery
htc_fastboot flash recovery (through different folder heaving related files)
Help me Solve that issue.
Click to expand...
Click to collapse
I recently unlocked bootloader to flash Magisk so I could have root access. I was getting the same error and found out that you must do the flashing in "download mode", not in fastboot or bootloader mode.
---------- Post added at 01:32 AM ---------- Previous post was at 01:31 AM ----------
hassanulhaq said:
I am currently running android 9.0 on htc dual sim model. i have unlocked my bootloader but whenever i tried to flash twrp or any other fastboot command after sending it says not allowed on production device.
target reported max download size of 536870912 bytes
sending 'recovery' (46340 KB)...
OKAY [ 1.320s]
writing 'recovery'...
FAILED (remote: Not allowed on PRODUCTION device)
finished. total time: 1.355s
i have tried both commands
fastboot flash recovery
htc_fastboot flash recovery (through different folder heaving related files)
Help me Solve that issue.
Click to expand...
Click to collapse
I recently unlocked bootloader on my HTC U11 to flash Magisk so I could have root access. I was getting the same error and found out that you must do the flashing in "download mode", not in fastboot or bootloader mode.

Download mode
CiroConsentino said:
I recently unlocked bootloader to flash Magisk so I could have root access. I was getting the same error and found out that you must do the flashing in "download mode", not in fastboot or bootloader mode.
---------- Post added at 01:32 AM ---------- Previous post was at 01:31 AM ----------
I recently unlocked bootloader on my HTC U11 to flash Magisk so I could have root access. I was getting the same error and found out that you must do the flashing in "download mode", not in fastboot or bootloader mode.
Click to expand...
Click to collapse
How to do that in download mode?

hassanulhaq said:
How to do that in download mode?
Click to expand...
Click to collapse
hi, sorry for the late reply, my brother "borrowed" my phone for a couple weeks and he did a factory reset. I don't have my phone yet, hopefully I won't have to unlock the phone again or flash Magisk into the bootloader again either...
To unlock the bootloader, I followed this nice and detailed tutorial here:
https://www.getdroidtips.com/unlock-bootloader-htc-u11/
Click to expand...
Click to collapse
.
Then I followed Magisk's official tutorial on how to flash it without a custom recovery... here
https://savegyd.com/magisk-root-tutorial/
Click to expand...
Click to collapse
... just go to the "How to install Magisk with ADB and Fastboot (without custom recovery)" section and read it carefully, but instead of rebooting the phone into fastboot mode, I had to do it all in download mode.
I I did not install TWRP custom recovery, I manually patched the stock "boot.img" file with Magisk and then flashed the patched boot with this command with the ADB tool in Windows (phone in download mode):
fastboot flash boot patched_boot.img. I wanted to keep HTC's stock recovery.
Then I rebooted the phone into Android, and opened "Magisk" app in Android to make sure the root was working...
I didn't have internet connection in my phone (data connection or wifi), I did it all offline.
If you don't have the locked "boot.img" you must check the exact version of your installed Android OS and download the correct RUU file. Then you can extract the boot.img from it, patch it with Magisk, then flash it into the phone.
I did it in download mode as it was failing in fastboot mode. Make sure to enter download mode when you restart your phone, not fastboot mode. I'm not responsible if you brick your phone. My phone is the "Global" version from India (6GB RAM, 128GB internal storage).

issue resolved
CiroConsentino said:
hi, sorry for the late reply, my brother "borrowed" my phone for a couple weeks and he did a factory reset. I don't have my phone yet, hopefully I won't have to unlock the phone again or flash Magisk into the bootloader again either...
To unlock the bootloader, I followed this nice and detailed tutorial here: .
Then I followed Magisk's official tutorial on how to flash it without a custom recovery... here
... just go to the "How to install Magisk with ADB and Fastboot (without custom recovery)" section and read it carefully, but instead of rebooting the phone into fastboot mode, I had to do it all in download mode.
I I did not install TWRP custom recovery, I manually patched the stock "boot.img" file with Magisk and then flashed the patched boot with this command with the ADB tool in Windows (phone in download mode):
fastboot flash boot patched_boot.img. I wanted to keep HTC's stock recovery.
Then I rebooted the phone into Android, and opened "Magisk" app in Android to make sure the root was working...
I didn't have internet connection in my phone (data connection or wifi), I did it all offline.
If you don't have the locked "boot.img" you must check the exact version of your installed Android OS and download the correct RUU file. Then you can extract the boot.img from it, patch it with Magisk, then flash it into the phone.
I did it in download mode as it was failing in fastboot mode. Make sure to enter download mode when you restart your phone, not fastboot mode. I'm not responsible if you brick your phone. My phone is the "Global" version from India (6GB RAM, 128GB internal storage).
Click to expand...
Click to collapse
Issue was resolved. My phone's bootloader was unlocked and and top of all it got pie update on unlocked bootloader with rooted phone and updated to android pie, then it started creating random issues like phone booting time was around 10 to 15 mins and i was getting above mentioned error. whenever i was booting to download mode my system was not detecting my phone but in fastboot mode it was detecting (kind of strange issue)... which turns out to be a cable issue. Once i changed my cable my phone was detected in download mode. So i re-locked the bootloader and then again flashed the firmware everything came to normal. Phone is up and working fine and thanks for help again.

Pixel 3a - stuck on BootLoader with: error boot prepar

Hello,
I followed the steps on these two links:
https://forum.xda-developers.com/pixel-3a-xl/how-to/how-to-root-pixel-3a-3a-xl-twrp-t3928868
https://www.**********.com/unlock-pixel-3a-bootloader-and-root-pixel-3a-3a-xl/
To root my Pixel 3A. I unlocked it successfully, and then I did the final step of this command:
fastboot flash boot magisk_patched.img
But now my device is stuck on the bootloader screen. The bottom lines say:
Device state: unlocked
Boot slot: b
Enter reason: error boot prepare
I tried the options on the boot loader (rescue mode, recover mode, restart bootloader, powering off and restarting) but it only takes me back to the bootloader screen with same error.
From my MAC, I can still do the commands:
fastboot reboot (which does reboot the phone)
and
fastboot flash boot magisk_patched.img, which shows this:
Sending 'boot_b' (29136 KB) OKAY [ 0.760s]
Writing 'boot_b' OKAY [ 0.189s]
Finished. Total time: 1.219s
But not sure what else I can do to get out of the bootloader screen
Any help would be appreciated, as the phone is effectively bricked

DarthLuch said:
Hello,
I followed the steps on these two links:
https://forum.xda-developers.com/pixel-3a-xl/how-to/how-to-root-pixel-3a-3a-xl-twrp-t3928868
https://www.**********.com/unlock-pixel-3a-bootloader-and-root-pixel-3a-3a-xl/
To root my Pixel 3A. I unlocked it successfully, and then I did the final step of this command:
fastboot flash boot magisk_patched.img
But now my device is stuck on the bootloader screen. The bottom lines say:
Device state: unlocked
Boot slot: b
Enter reason: error boot prepare
I tried the options on the boot loader (rescue mode, recover mode, restart bootloader, powering off and restarting) but it only takes me back to the bootloader screen with same error.
From my MAC, I can still do the commands:
fastboot reboot (which does reboot the phone)
and
fastboot flash boot magisk_patched.img, which shows this:
Sending 'boot_b' (29136 KB) OKAY [ 0.760s]
Writing 'boot_b' OKAY [ 0.189s]
Finished. Total time: 1.219s
But not sure what else I can do to get out of the bootloader screen
Any help would be appreciated, as the phone is effectively bricked
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Click to collapse
Sounds like your magisk file is either the wrong version or corrupted. Download the full Google image, extract the boot.img from that and ash that image file using the fastboot flash boot boot.img command. Alternatively you could download the mvk kernel from here on xda and flash that. It's pre-rooted.

adm1jtg said:
Sounds like your magisk file is either the wrong version or corrupted. Download the full Google image, extract the boot.img from that and ash that image file using the fastboot flash boot boot.img command. Alternatively you could download the mvk kernel from here on xda and flash that. It's pre-rooted.
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Click to collapse
Thanks for that.. For whatever reason the MVK_Sargo_v10.22_magisk_patched.img version did not work, but the MVK_Sargo_v10.21_magisk_patched.img one did!

DarthLuch said:
Thanks for that.. For whatever reason the MVK_Sargo_v10.22_magisk_patched.img version did not work, but the MVK_Sargo_v10.21_magisk_patched.img one did!
Click to expand...
Click to collapse
If 21 worked but 22 didn't... Going from my faltering memory that means your not on March security, your on feb or earlier. 22 only worked on March, i am running it myself.

I got stuck here, too... I used the flash tool (flash.android.com) and it put me back to stock after about a 20 minute progress bar crawl

I have the same problem can someone help me?

YYa solucionaste ?