A painful experience - see below - taught me that a NANDROID backup isn't enough.
I had to find a PIT file, a bootloader and a modem.
What else does one need to be able to get back to an earlier version, and is there some software to do that
automatically?
I've tried an Android-5.0 for which I had to flash the boot loader and the modem, as well.
The Android-5.0 system booted well but it turnt out that I got insurmountable difficulties with WLAN
authentication. Therefore I wanted to go back to Kitkat (4.4.2) which I had backed up by TWRP.
I could restore the system but got a boot loop - no wiping helped.
Then I tried to install a stock 4.4.2 system but ODIN-3.09 has stalled for more than an hour such that I had
to kill it. Now my device was broken. Luckily I did find a suitable PIT file, boot loader and modem.
Even then ODIN didn't succeed. With the help of Philz-Touch-Recover I could reformat some partitions.
Only after that ODIN succeeded - together with the PIT file - to flash the bootloader and the modem,
Only now, I could boot into the old version.
Many thanks for a hint,
Helmut.
I had to find a PIT file, a bootloader and a modem.
What else does one need to be able to get back to an earlier version, and is there some software to do that
automatically?
I've tried an Android-5.0 for which I had to flash the boot loader and the modem, as well.
The Android-5.0 system booted well but it turnt out that I got insurmountable difficulties with WLAN
authentication. Therefore I wanted to go back to Kitkat (4.4.2) which I had backed up by TWRP.
I could restore the system but got a boot loop - no wiping helped.
Then I tried to install a stock 4.4.2 system but ODIN-3.09 has stalled for more than an hour such that I had
to kill it. Now my device was broken. Luckily I did find a suitable PIT file, boot loader and modem.
Even then ODIN didn't succeed. With the help of Philz-Touch-Recover I could reformat some partitions.
Only after that ODIN succeeded - together with the PIT file - to flash the bootloader and the modem,
Only now, I could boot into the old version.
Many thanks for a hint,
Helmut.
xda-developers