Context
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.
Expected behaviour
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.
Observed behaviour
For Fairphone OS I tried from this link:
fp2-gms-19.11.2-manual-v2.zip
and verified the downloaded md5 as: e1601288869f99143b664ea98f825760
.
For Fairphone Open (OS) I tried from this link:
fp2-sibon-21.03.0-rel.2-manual.zip
and verified the downloaded md5 as: b3666e0a34efcec349f206f53ea98445
.
For both files, I receive the error:
Invalid zip file format!
Hypothesis
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: upgrade
and 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.
Question
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?