FP4: Questions about upgrade from /e/OS 1.5r to 1.6s (stable) via sideload

[Truhvanor]

Greetings,
after reading the Upgrade-Guide (/e/OS Version Upgrade) I’m still left with some questions, I hope somebody can provide an answer or two. First some info about my Phone:

• FP4, bought from Fairphone
• Last stock FP-OS version that ran on the device: FP4.FP3R.A.099.20220112_factory.zip
• Current /e/OS version: 1.5r - Stable (security patch: September 2022; vendor patch: September 2022)
• Bootloader: Locked
• OEM Unlock: Disabled (but I still have the required key)

I’ve installed /e/OS myself back in April (I think it was /e/OS 0.22 - Stable back then).
Now to the actual questions:

1. The Upgrade-Guide suggests some devices need to install a current stock ROM before upgrading to /e/OS 1.X s, is the FP4 one of these devices or do the /e/OS builds contain the vendor security patches (probably yes but I want to be sure)? If the answer is yes, installing a stock ROM is necessary the following questions can be ignored.
2. If the device does not require the installation of a current stock ROM, will sideloading the current /e/OS 1.6s zip via adb suffice to upgrade both system partitions (a and b)? So the OS’s recovery features will work if something goes wrong later on.
3. Is OEM Unlocking required for sideloading?
4. Of course I will create a backup of my data in case something goes wrong but upgrading via sideload does not cause a factory reset after upgrading or does it?

I think that’s it for the moment, I hope someone might share their insights.
Thank you and Cheers!

[stanwood]

The FP4 can be easily OTA upgraded via the settings menu => check for updates.

The current /e/OS version is: 1.6s (Android 12) which works pretty fine.

No need to flash your device via a computer.

Also, the upgrade function via “adb sideload” described in the documentation does not work for the Fairphone 4. See comments below:

Fairphone - FP4 - FP4 - Documentation Suggestions

Hi all, It seems that the guide to manually upgrade / update FP4 is wrong. According to this guide: https://doc.e.foundation/devices/FP4/upgrade This procedure doesn’t work to upgrade manually the device. Indeed, “adb sideload” action can’t perform the IMG-e build here: https://images.ecloud.global/stable/FP4/ Error message warns a “mismatch signature” See logs in attachment. Currently only OTA upgrade is possible unless unlocking bootloader and wipe all data. Maybe this guide would need …

So let’s keep it easy

[Truhvanor]

Oh cool, that’s convenient! Thanks! I was a bit confused as the guide also mentioned version upgrades would be hidden by the systems update feature but the upgrades were actually displayed and my phone keeps reminding me there are upgrades available.
One last question about the slots (or partitions): Somewhere I’ve read that installing the upgrade via the system’s update/upgrade feature would only upgrade the currently active slot (“a” for my device). Since version rollbacks are not possible, would upgrading this way would render the second slot (“b”) useless or does it also get upgraded?

[stanwood]

I’m not a specialist, but I think that slot b is a kind of buffer for installing updates.
But one thing is certain: You don’t need to do anything with this B slot.

The update process will well do the job, including updating firmware when those are provided by The Fairphone company to the /e/ foundation.

[Truhvanor]

Thank you very much for the clarifications! Cheers!

[ff2u]

@Truhvanor

I’ve read that installing the upgrade via the system’s update/upgrade feature would only upgrade the currently active slot

I think it’s wrong what you read.
OTA upgrades save the new version to the alternate slot (so to “b” if you’re currently running from “a” and to “a” if you’re currently running from “b”). When this preparation is completely done you just reboot from the alternate slot to start the new version. If anything goes wrong on first boot attempts the OTA update function can switch back to original slot.