[Sony Xperia M] XDAXperiaM:
Hey bro, tnx a lot for your reply. Good hint. Tried to install according your instruction, partially in some way an advance to before: ...

1. Boot into TWRP recovery

->fastboot flash boot bootAOSP.img

->TWRP3.0.2.0 booted properly and this was new I could it would fully work again!

-> This step OK

2. Wipe system, data, cache, dalvik - cache

->TWRP3.0.2.0 boot - and deleted each single partition bit by bit (I had to hurry), because: After 29. sec. reboot.

The system, cache, data, sd card etc. were properly mounted and no errors were shown

-> This step OK

3. Flash ROM

-> ->TWRP3.0.2.0 boot and installed ROM: aoscp_nicki-3.6.3-20170610-unofficial.zip

will start to install the ROM without error message, until the screen turns black und is interruptecd by -> reboot

After this mount "system" error is indicated and with the help of flashtool 09.18.6 the *.ftf firmeware, see above, will properly fix the partiation and everything is mountable again -> so I ran over the proceedure several times.

At least an advance, compared to the state before, where only TWRP 2.8.6.0 was fully operational ( until -> reboot after approx. 29 sec.)

Some how the reboot has to be stopped.

I found a log file unter /cache/recovery/last_log (opend it shortly before the . reboot occoured) an here are the boot protocols. I saw Jan 2020

So some old system files still remain in the linux depths oif the android which seem to cause the reboot.

I managed to extract via TRWP the recovery.log to sd card. I don't know how to attach the log-file here. Just ask for it via PM.

The pity is, whatever I (sucessfully) do - I have appro29 sec. time. Its like mission impossible and the bomb :). If this time lock could be broken things would appear possible. Shell script to fix (but I don't have any Idea)?

Best regards an Thank you for your help/ideas.

Dirk

P.S.:

What I tried as well:

Somehow it has a similar effect like here: reboot after 30 sec. reason Firmware corrupted

https://xdaforums.com/xperia-z/help/solved-phone-disconnects-flashmode-t2240960/page2

so maybe someone has proper tested firmeware for 4.1 or 4.3...

Boot loop issue. A pity this didn't work

https://xdaforums.com/showthread.php?t=2513568&page=2

because system.sin flash doesnt finish, because the mobile is switching off due to reboot after 29 sec.

I also tested backup C1905 stock firmware

https://xdaforums.com/showthread.php?t=2703161

CWM and everything installs nicely until comes to flash proceedure, which is nicely starting, but interrupted by the continious reboot...

Maybe a little chance is this, but I can't manage to find sony flash tool 0.6.6 and according driver. Maye somebody still has the stuff?

Solve system.sin flashing error with sony flash tool 09.18.8.8 and sony flash tool 0.6.6

https://xdaforums.com/showthread.php?t=2658952&page=24

Page 24:

Hi all, if anyone is having trouble flashing with flash tool because usb debugging isn't enabled error then do this procedure.......

1. Dowload latest flash tool 0.9.18.8 and also version 0.6.6

2. Try use the latest version first to Flash the tft rom. NOTE: remember the file it has error flashing e.g on my experia sp file system.sin was not able to Flash bcoz usb debugging error (enable usb debugging and unknown sources) ALL THE REST of the files flashed ok!

3.try flash again the rom but this time tick system.sin (or error file) in flashtool to exclude it from flashing. Make sure all other files are included. Also tick all wipe caches options and flash rom without system.sin (or error file).

4. Flash procedure will work. Now disconnect phone and leave it off without restarting it.

5. Uninstall flashtool latest version 0.9.18.8 and install flashtool 0.6.6 old version and open it to Flash the same rom BUT THIS TIME only select the system.sin file (or error file) to be flashed and rest excluded. Make sure all wipe options in flashtool are enabled and Flash! THE FLASH WILL WORK WITHOUT USB DEBUGGING ERROR and your phone will be fixed!

Maybe a chance?