Zenfone 3 ZE552KL, system upgrade not possible

A long time ago I installed e/OS 0.13-2020120889008 on the Zenfone ZE552KL. This phone is used as a daily device and it runs reliably.
However, the updater app now already reminds upgrade to 0.22-2022214163416 but the update progress always fails, because apparently the TWRP recovery is not installed anymore. It must have been removed right after the install, because none of the updates could be installed in the last months (incompatible recovery system. The phone boots into “Android Recovery” and update is aborted with error code
E:failed to verify whole-file signature
Update package verification took 6.2 s (result 1).
E:signature verification failed
E:error: 21
Installation aborted
When booting directly into recovery (device or adb) it turns out TWRP is not present.

Is it possible to flash the TWRP recovery without resetting the whole device?

Hi @Nello,

Yes

https://doc.e.foundation/devices/zenfone3

Thank you! Sorry for my late reaction, I did not see it before.