Ultimately, I’d like to have a completely (or as far as feasible) self-compiled system on my FP2. And I think I currently have that, including a self-compiled recovery, as I’ve successfully followed the build instructions at [quote=“wiki, post:1, topic:11600”]
Compile your own FP2 ROM
[/quote] but without the [quote=“wiki, post:1, topic:11600”]
Modifying the official image by installing a modified recovery and side-loading the packages you want
part (I’ve used Max_S’s approach for rooting) and a
recovery.img image was part of the build results that I flashed onto my FP2. After flashing that and other images from the build results to the partitions of the respective name, the recovery mode’s menu showed my computer’s username, as did the kernel and system info within Android, so I’m reasonably confident that building and flashing actually worked.
I’d now like to (temporarily) switch back to the official ROM (see below why) but hadn’t made any backups of it that I could flash onto my FP2.
In SatStat (installed from F-Droid), I noticed that no measurements for the sensors (acceleration/gravity, rotation, magnetic field, orientation, temperature, air pressure, light, relative humidity, proximity) were displayed. I don’t know whether FP2 has all of these sensors, but it must have some of them. I suspected it might be a problem with the app, thus looked for another one that would show sensor readings. Found and installed Androsens 2, but that also didn’t show any values. I then noticed that (e.g. in the pre-shipped SMS app) orientation didn’t change with the phone’s position, although auto-rotate was enabled in the settings.
So I now like to know whether I’ve got a hardware problem or a (probably kernel-/driver-/operating system-level) software problem that keeps Android from reading the sensors. As FP2 doesn’t seem to have an operating system independent (started from the recovery mode, IIRC) test mode as the FP1 had, I think the easiest way to check is by trying with the official ROM. Unfortunately, I didn’t test that when I still had that installed (but I think at least auto-rotate worked) and hadn’t made backups before flashing my self-built images.
I was able to revert the kernel to the stock one by extracting and flashing
boot.img from http://storage.googleapis.com/fairphone-updates/FP2-gms36-1.1.7-ota.zip
But I don’t know how to flash the images for the other partitions (especially
system.img) from the zip file. They don’t seem to be included, or at least not in
.img format. Applying the ZIP file whole (without extracting manually) through the recovery menu failed due to the signature verification that my self-built recovery seems to do.
Ah, I did see that, but didn’t recognize it was what you were referring to, as I thought you were talking about disabling the stock recovery’s validation mechanism by changing its source, rather than using a completely different recovery system.