Out of a sudden stuck in boot-loop

Help Fairphone 3
,
1

FP3+, 64GB, bought 2023, Lineage installed, worked for two years.

Recently got stuck in boot-loop, specifically: animated logo shows up for about two seconds, then phone reboots.

Tried with recovery boot and adb to access userdata partition, but image cannot be copied, after about 1 GB phone crashed and reboots.

Tried factory reset and re-installing (new) Lineage, but sideload gives error:

ERROR: recovery: failed to verify whole-file signature
Update package verification took 46.9 s (result 1).
ERROR: recovery: Signature verification failed
ERROR: recovery: error: 21

What could be the cause? Internal memory defect? Is there anything one can do? Is that repairable?

Any help is much appreciated!

2

Wondering, is there anyone who can help? Or are these questions somehow stupid?

3

Your questions are certainly not stupid. When you say factory reset do you have a “Stock recovery” or “Lineage recovery” .img upon your FP3 now? As all data gone now I would try to return to FairphoneOS and start again from scratch installing LineageOS.

4

So far Lineage recovery. I’ll try fairphone original, why not, it cannot get worse anymore.

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Besides, since the factory reset is pretty fast, I guess it’s just creating a new filesystem or something like this.

In case it’s a memory issue, is there by chance something like fsck/checkdisk available? Since obviously parts of the memory are still ok.