[Lenovo Zuk Z2 Pro ROMs, Kernels, Recoveries, & Oth] tiggerle666:
### UPDATE: PROBLEM SOLVED - I WILL INCLUDE MY STEPS HERE IN THE COMING DAYS FOR OTHER USERS THAT MAY HAVE DIFFERENT PROBLEMS '###

Hello guys, I had troubles installing the AOSP ROMs. The installation fails with loads of errors, see below.

After unbricking my phone (due to a modem update, see my other post if interested) I flashed the stock ROM ZUI 2.5 and 3.0 (I tried both) with QFIL and then tried to install the AOSP ROM with TWRP after transfering the .zip to the internal /sd-card. I tried the latest two original AOSPextended versions from @dmd79 for Android 9 and 10. I had flashed the AOSP ROM in the past without problems (the phone is still unlocked but not rooted), but after the brick everything is complicated now. Installing TWRP versions was also very tricky because some would never start up and others would need double or triple flash to start working (see my other post on that topic if interested). So I went back to 3.1.1.0 and then finally 3.2.3.1 (which has direct sd-card access). The problems and errors I have/had:

- In Fastbood menu I can see that product_name, bootloader version, baseband version are all EMPTY (product name is therefor displayed as QC_Reference_phone).

- As I had to unbrick my phone by flashing an older stock ROM ZUI 2.5, I first tried this one (and later ZUI 3.1) as a base to wipe & install AOSP.

- When I try to install any of these AOSP ROMs in TWRP I get E3004_ "This package is for device: z2_row; this device is ." Updater process ended with ERROR 7. So of course I tried to eliminate the first line of the updater file to proceed the installation process. What troubles me is that in the system/build.prop all the variables such as ro.product.device are correctly labelled (I also tried to install it before wipe, but no difference)

- After eliminating the first line from the updater file you'll end up with the next problems. the installation would stop at abort("E1001: Failed to update system image.") and if you delite that line, then it stops at abort("E2001: Failed to update vendor image."). I have read multiple threads concerning this issue but nobody had a proper solution for these errors. And simply deleting the abort function doesn't lead anywhere. In the end the updater script can run through from first to last line, after "sucessful" installation the OS won't start (some parts seem to have been installed to the specific directories, as far as I could see in the TWRP file manager), the phone only starts to fastboot bootloader and turns black if you force a system start. Needless to say that it took lots of time because I always did a full wipe (data, cache, dalvik, system) but after each failed installation I had to use the deep flash cable (see my other posts) to be able to flash a ZUI stock ROM again and transfer modified AOSP versions...

- Maybe it is because of the following error that now occurs: "Skipping Digest check: no digest file found". I am getting this error before and after wiping the ZUI ROM? Don't know what that error means...

- I tried to CHMOD 755 directories and checked for file system Ext4 as suggested in some threads but of course no change.

Finally I flashed ZUI 1.9 with QFIL. AOSP installations failed. I tried to update directly to 3.5 using the update.zip provided in the other thread here, but installation didn't even start. Then I flashed my original bootloader from the very beginning in 2017 (I still had a backup), which relocked my bootloader. After reflashing ZUI 1.9 I then did a manual OTA all the way up to ZUI 4.0. Battery drain was remarkable in low-use state, just 20% in the whole day compared to 50% in AOSP10 under similar conditions. But ZUI_4.0 was not so much fun because the bootloader was then locked again (although displayed as unlocked!), using fastboot it was not possible to write to /recovery and flash TWRP. Had to figure this solution out as well, unlock within ZUI settings AND do the fastboot -i 0x2b4c oem unlock-go thing again, ha! Now finally I could flash TWRP once again and then, then the normal unedited AOSP zip could be installed.

Hope it helps anyone