[P8lite Q&A, Help & Troubleshooting] icewewe:
Hi all,

Interesting problem. I've been updating some P8 Lite units that were shipped to us with a single SIM ROM with dual SIM ROM. I've already done two phones without issues (both ALE-L21). Onto the third phone (also ALE-L21), and this time there's a problem.

I'm not quite clear if the HiSilicon Kirin 620 and HI6210SFT are the same chipset or not. An answer to this would be helpful!

Steps taken:

Unlocked bootloader via Huawei website. Fastboot says PHONE Unlocked and fastboot oem get-bootinfo replies: (bootloader) unlocked

Flashed boot, recovery, cust, and system.img via fastboot following the guide (using dual SIM unbrick files)

Phone does not boot past Huawei logo, I get a black screen and then after a minute or so it reboots

Pretty odd, since I've done this on two other phones of the same model and the process worked without any issues.

TWRP 2.8.7 does not boot on the phone (black screen and reboot to Huawei logo)

TWRP 3.0.2 does boot.

Unfortunately I didn't think to take a backup of the system before I started this since I'd done it twice before without problems.

Here's what I've tried to do to get this phone to boot again:

Took TWRP backup of another ALE-L21 running B584 and restore it. Result: bootloop/not booting past Huawei logo

Flashed B052 via fastboot from here. Result: bootloop/not booting past Huawei logo

Flash recovery.img from the guide (not sure which OS version this is based on) and put UPDATE.APP for B052 on sdcard\dload\UPDATE.app. Result: black screen after Huawei logo, no activity

Tried the above with UPDATE.APP from B584. Result: black screen after Huawei logo, no activity

Using Huawei eRecovery from fastboot. Result: "getting package info failed"

I know the phone isn't bricked, because TWRP 3.0.2 still boots.

However, I cannot for the life of me get any Huawei OS to boot on this phone anymore. I'm using fastboot for everything (Linux) and I don't have any problems to flash:

$ fastboot flash boot BOOT.img

target reported max download size of 471859200 bytes

sending 'boot' (21706 KB)...

OKAY [ 0.887s]

writing 'boot'...

OKAY [ 1.692s]

finished. total time: 2.580s

$ fastboot flash recovery RECOVERY.img

target reported max download size of 471859200 bytes

sending 'recovery' (34280 KB)...

OKAY [ 1.420s]

writing 'recovery'...

OKAY [ 2.615s]

finished. total time: 4.036s

$ fastboot flash cust CUST.img

target reported max download size of 471859200 bytes

sending 'cust' (218981 KB)...

OKAY [ 8.815s]

writing 'cust'...

OKAY [ 5.691s]

finished. total time: 14.507s

$ fastboot flash system SYSTEM.img

target reported max download size of 471859200 bytes

sending sparse 'system' (460798 KB)...

OKAY [ 24.211s]

writing 'system'...

OKAY [ 10.338s]

sending sparse 'system' (460385 KB)...

OKAY [ 23.630s]

writing 'system'...

OKAY [ 10.617s]

sending sparse 'system' (460747 KB)...

OKAY [ 23.682s]

writing 'system'...

OKAY [ 11.319s]

sending sparse 'system' (457010 KB)...

OKAY [ 23.684s]

writing 'system'...

OKAY [ 10.537s]

sending sparse 'system' (443304 KB)...

OKAY [ 23.432s]

writing 'system'...

OKAY [ 10.011s]

finished. total time: 171.461s

My next step would be to try a custom ROM, but there isn't much choice here of flashable zips, and all the custom ROMs seem to be broken or missing features. what I really want is to get this phone back to booting the Huawei OS, but this is seeming impossible.

I'm using Ubuntu 16.04 amd64 and have no issues with adb/fastboot or drivers.

Does anyone have any ideas why this phone refuses to boot after the attempted dual SIM conversion?