FP4 - update via adb sideload wont work

[rofl]

i try to update my FP4 using adb-sideload.
after starting the phone to the e-recovery (it starts actually only to this due to “active slot = b”) i enabled adb on phone and started initialised the update (mac terminal, “% adb sideload IMG-e-1.21.1-s-20240325389527-stable-FP4.zip”).
Unfortunaltly i get the error:
"Installing update…
E: Failed to Find update binary META-INF/com/google/android/update-binary

Install completed with status2
Installation aborted"

As far as i found out, the “IMG-e-1.21.1-s-20240325389527-stable-FP4.zip” seems to be only for initial installation, but not for updating?
Is ther any other image i can use for updates?

[mihi]

Do you have a locked bootloader? Sorry for the question but just to get that out of the way

[rofl]

unffortunately yes - and i cant unlock it (first i do not want to lose data and anyway it did not work due missing “rights”).
the update was an idea to bypass this issue Fairphone 4 - stuck on recovery screen - need instructions for further action - #4 by rofl , but i am afraid i run/stuck in this:
https://forum.fairphone.com/t/trapped-in-fastboot-mode-with-locked-bootloader-and-corrupted-custom-rom/80985

[mihi]

Well with locked bootloader there is no sideloading

Why do you want to sideload?

[eosuser]

Is sideloading a way to “clean install” an OS?

[mihi]

It can be. Usually it is used to update. for example from 1.20-s to 1.21-s.

Lf you are doing a clean install from recovery it is also possible.

What is your problem, what was your goal?

[rofl]

the hope was to get a fixed OS by upgrade the system using sideload - sometimes (on computers) this works.

[piero]

1. Download the file
   https://ota.ecloud.global/stable/FP4/e-1.21.1-s-20240325389527-stable-FP4.zip
   or
   https://ota.ecloud.global/stable/FP4/e-1.21-t-20240323388918-stable-FP4.zip

2. Reboot to recovery mode

3. Apply the “update” via adb sideload

[rofl]

thanks, the sideload proceeded:
adb sideload e-1.21.1-s-20240325389527-stable-FP4.zip
Total xfer: 1.00x

Phone shows step 1/2 and 2/2 done.
but after reboot the phone unfortunatly still starts with active slot b and fastboot --set-active=a did not work due locked fastboot.

[piero]

And no option to change slot in recovery ?

as it indicate active slot…

[rofl]

no chance, i stuck in recovery loop.