I’ve extracted the boot.img and vendor_boot.img files from https://dlcdnets.asus.com/pub/ASUS/ZenFone/ZS590KS/UL-I006D-ASUS-30.12.112.82-1.1.31-user.zip The firmware of the latest android 11 from Asus. I used the payload_dumper.py script on payload.bin which resulted in all the partitions being exported to .img format.
I flashed those back to the phone’s boot and vendor_boot partitions and the phone boots without problem.
The boot loop is probably caused by the fact I can’t get into recovery (just boots back into bootloader), so I can’t install the OS.
I’ve tried the recovery images for both /e/1.1 and 1.0.
Edit:
I should up my searching skills. Temporarily Booting a custom recovery using fastboot -- help please - #15 by eboelens
This guy has the same problem. I’ll see if I can try his way… Tomorrow 