You can try. This looks like a TWRP backup. TWRP is a custom recovery program.
I have tried to restore a complete TWRP backup two times on my Fairphone 3, unsuccessfully, both times ending in a bootloop. Just to manage expectations, I myself obviously don’t know how to do that so that it works afterwards .
TWRP will look for backups to restore in the following directory structure either in Internal Storage (which isn’t an option in this case here) or on an SD card in the phone (includes the serial number of the phone you got with fastboot devices):
TWRP
BACKUPS
A209HLH80202
(some directory name TWRP puts together automatically, shouldn’t be too important if you have to make one up)
here are all these files
If you have this structure already, just copy it to the SD card as it is.
With the phone in Fastboot Mode fastboot boot twrp-whatever-else-is-in-the-filename.img
TWRP starting the first time (or not being able to access the data partition) will ask whether to keep the system partition read-only or to allow modifications … keeping it read-only is the safe choice, this doesn’t hamper restoring.
From the TWRP main menu:
Restore - Select Storage (select Micro SD Card) - select the backup to restore - select the partitions to restore - Swipe to restore
(Can’t have a look right now, I hope that’s about right from memory.)
When the restore is done, reboot.
In case the restored state of the phone doesn’t boot, here’s another shot at it …
I don’t know how to do that, and luckily you don’t need to do that, because …
… there simply is no recovery partition on the Fairphone 3. You can’t flash TWRP to the Fairphone 3 this way.
Installing TWRP would work differently, but this doesn’t help now.
This should work with an unlocked bootloader.
What happens on the phone when it should be booting TWRP?
Apart from the warning screen displayed due to the unlocked bootloader, there could be a second screen coming up, where you would have to press the power button to proceed, else the phone would reboot after 30 seconds or something like this.
Once you downloaded e.g. the A.0111 (an earlier version of the stock OS, you can update it once it’s running again) ZIP file and unzipped the partition images in it to where your fastboot command is, you can flash the partition images to the phone.
Determine the active slot first with fastboot getvar current-slot
That will give either a or b.
Let’s say you still have slot b active.
You could then …
These Invalid sparse file format at header magic messages are ok, according to the forum, flashing should have worked nonetheless.
Else … I searched the internet for a picture of the screen I mentioned … you are certain you don’t get this one here at some point, which would then reboot the phone after 30 seconds if you don’t press the power button to proceed with booting?
This can easily be missed.
(This message can be kind of a nuisance and it can be deactivated once Android or TWRP can be booted successfully … perhaps just with pressing the power button there to proceed with booting.)