To perform a bit more testing in a script that (semi-)automatically switches between Fairphone OS and LineageOS on the FP2, I would like to revert back from LineageOS to FairphoneOS (or Fairphone Open), using TWRP.
Basically I use:
adb sideload <somezipfile>.zip
somewhere in the code to flash a different OS on the FP2 whilst booted into TWRP. For LineageOS this works, however, I am experiencing some difficulties going back to Fairphone.
I would expect sideloading either of the operating zip files using TWRP (with proper data erasing before and after etc.) would successfully flash the Fairphone (Open) OS on the phone.
For Fairphone OS I tried from this link:
fp2-gms-19.11.2-manual-v2.zip and verified the downloaded md5 as:
For Fairphone Open (OS) I tried from this link:
fp2-sibon-21.03.0-rel.2-manual.zip and verified the downloaded md5 as:
For both files, I receive the error:
Invalid zip file format!
I expect this might be because those files seem to be for updating the Fairphone (Open) OS from a situation that already has the Fairphone (Open) OS installed, instead of being intended for flashing the Fairphone (Open) OS newly on the device (without LineageOS installed).
This hypothesis is based on the usage of the words:
switch describing the used
.zip files for Fairphone Open OS, and based on the term
manually update for the Fairphone OS. I am not looking to update/upgrade/switch from an existing Fairphone (Open) OS. Instead I inted to flash/install the Fairphone OS regardles of its current/previous OS. This difference makes me think the provided
.zip files might not just be an OS image but some form of script that builds on the previous Fairphone (Open) OS, which is non-existant in this case. This in turn might result in the used
.zip files not being suitable for sideloading.
Hence, I would like to ask: which
.zip file should I use to sideload either the Fairphone OS, or the Fairphone Open (OS) using TWRP from a device that has/had LineageOS installed?