Unbrick BL unlocked device (HSTool nor DLOAD method working)

[mikeos]

Another method for unbricking EMUI 9 devices. For advanced users (not mentioning links to TWRP, to FullOTA factory images... there are other threads dedicated to that). Tested on Mate 20 Pro.
This method should help when:

1. Device has bootloader unlocked (unusable for locked bootloaders)
2. System fails to boot. HiSuite (HSTool) restore method does not work (fails in stage "Install recovery") nor does DLOAD method work (after VolUp+VolDn+Pwr action system continues booting or ends in 5% Installation and bootloops).
3. Fastboot mode is working
The reason might be wiped/corrupted eRecovery paritition.
Huge credits and thanks to @OldDroid for having educated me about eRecovery and about flashing it.

Steps:
1. Download FullOTA factory image
2. Extract UPDATE. APP file
3. Extract ERECOVERY_KERNE.img, ERECOVERY_RAMDI.img, ERECOVERY_VENDO.img, ERECOVERY_VBMET.img (guide:
OpenKirin - guide to extract partition images)
4. Boot into fastboot
5. Install and boot TWRP (

fastboot flash recovery_ramdisk twrp.img

)
6. Copy (e.g. via MTP, while connected to the computer) the 4 previously extracted images to internal storage or SD
7. Enter TWRP shell and execute:

ls -l /dev/block/bootdevice/by-name/

8. Check partition names, in case of Mate 20 Pro they are:

erecovery_kernel /dev/block/sdd37
erecovery_ramdisk /dev/block/sdd38
erecovery_vbmeta /dev/block/sdd53
erecovery_vendor /dev/block/sdd39

9. Copy the extracted files into corresponding partitions:

dd if=./ERECOVERY_KERNE.img of=/dev/blck/sdd37
dd if=./ERECOVERY_RAMDI.img of=/dev/blck/sdd38
dd if=./ERECOVERY_VENDO.img of=/dev/blck/sdd39
dd if=./ERECOVERY_VBMET.img of=/dev/blck/sdd53

10. Reboot to fastboot and flash stock recovery via

fastboot flash recovery_ramdisk stock_recovery.img

Now you should be good to go for DLOAD (recommended for soft-brick recovery) and HSTool methods.

 

[ReyneBow]

Would this be for Error mode?
func no : 11 (recovery image)
error no : 2 (load failed!)

This error is what happens when I try Dload.

 

[mikeos]

Would this be for Error mode?
func no : 11 (recovery image)
error no : 2 (load failed!)

This error is what happens when I try Dload.

Depends on what is actually broken. If the error is caused by a broken eRecovery image, than this could help. I can't tell, the error codes displayed tell me nothing. One can also update eRecovery if it is extracted from a more recent firmware - e.g. EMUI 9.1.