Tips or considerations before flashing another ROM?

Hi!!! A few days ago I finally purchased a FP4, my first ever expensive but cool smartphone <3 I will get my hands on it this afternoon, and I wanted to check with the community: Anything I should know before flashing CalyxOS on it?

I want a degoogled phone, so I’m pretty certain that I want a different ROM (if I’m not mistaken, the default one is not degoogled in any way). From the options, CalyxOS sounds cool, and I have flashed a few smartphones before (LineageOS and before that, Cyanogenmod), so I’m no stranger to the process.

  • My main concerns are about the warranty status, as I won’t be testing the phone under the stock rom for long. I was thinking of testing everything for a day at most with the stock, but I want to jump fast to Calyx. Anything special or prone to factory defects that I should check while on stock? Any trouble with the warranty support after flashing?

  • Other than that, for anyone running Calyx, any known bugs or anything weird? I’m planning on running a convergence style system with android desktop (the hidden mode) + termux-x11 + xfce, so if there are problems enabling the USB-C video output that would be a big problem. Can anyone confirm that the video output works on the non-stock roms?

And that’s all!!! Thank you so much for your help, I’m a bit anxious but sooooo excited. If I manage to turn my FP4 into my main and only desktop (my current plan), I’ll try to document the process and keep you all updated.

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Hi and welcome, I would suggest you search and read a bit in the forum, there are already topics around this.

Just note its a user forum foe official Fairphone statements you would have to #contactsupport

Thank you!

I’ve been searching a bit around, but I may have skipped stuff…

For the warranty stuff I mostly wanted a bit of reassurance, what I have read seems to point that it’s all Ok about flashing.

For the CalyxOS+Video out I haven’t found any info in the forum, only mentions for the desktop mode in the stock rom. Maybe I should have made that the title…

Thanks in any case for guiding us lost newbies :slight_smile:

Hi Iris92

feel welcome here in the forum!

Not sure how much “de-googled” you would like to have your phone at all.
Here´s a pretty good analysis by a german security researcher that took a deeper look at CalyxOS’ traffic and behavior:

It´s in german but that´s no big hurdle nowadays, right? :wink:
Just pick your favorite translation service and read that article in your favorite language.

Essence of that article is:
CalyxOS is low-googled but their promise of being fully de-googled is (not yet) true


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I think thats the most official you can get here from other user reg. The warranty topic


Any trouble with the warranty support after flashing?

The primary problem seems to be a combination of design flaws and bugs that mean trying to lock the bootloader can brick the device to the point of requiring the device to be mailed to Fairphone’s service company to be reset. Fairphone refuses to fix the problems or provide a workaround (doing so would allow a serious unfixed security flaw to be exploited), and refuses to honour their warranty in this case, even if it happens through following instructions from their own support. They charge €34.50 for repair.

Realistically, however, given the security flaws with the device, locking the bootloader is likely not that helpful to begin with (the device trusts keys that have their private keys publicly available, and these are used to sign the stock OS).

Also, honestly, I see the usual “contact support” advice given in every context in this forum, and have seen few cases where contacting support has ended up being useful, especially for questions like these.

Can anyone confirm that the video output works on the non-stock roms?

Video output works fine with LineageOS. In fact, many features seem to work better in most non-stock ROMs than in stock, with a few exceptions for features that are problematic in the first place (eg, 48MP images).


Thank you for your answers!!!

About the warranty, ok, that sucks a little bit more than what I had previously read. I’ll be careful with the locking/unlocking stuff, thank you for the warning!

And for the video stuff, cool to know that at least on LineageOS it works!

Cool to know the official stance, thank you!

Aaaaaaaand that’s not cool :frowning: Still, thank you, I’ll do a double check and reconsider which rom to get, although I’ll go wiht calyx anyway… I mean, I still have an account with google, so it will be at least worlds better than my current stock android.

I can confirm it works fine on CalyxOS as well (mirrored / desktop mode) :slightly_smiling_face:

How usable it is depends on the USB-C dock you have. I only have a Steam Deck dock to test and that’s not fully supported, but there are several threads on the forum with recommendations for usable docks.

If you stick with the CalyxOS route, make sure to not lock the bootloader manually (especially don’t boot it and lock it afterwards!) and you should be fine. The device-flasher has checks in place to prevent you from bricking.

If you lock the bootloader with a custom key, like several ROMs do, the security model is still intact.
And there is no leaked EDL loader available (yet), so even the stock install is reasonably secure for the time beeing (not saying that trusting the test keys by default isn’t a very stupid idea)


Cool or not. I think it´s at least better to know about it.
“De-googled” does not mean at any time 100% “no google onboard”, it rather means <=100% de-googled
(and it´s up to you, your decisions how de-googled it will be :wink: )

I´ve never had a hand on CalyxOS so far and just experimented for a while with LineageOS on other devices (…and liked it; to be honest. However even my actual FP3 is still on stock - lazy me :face_with_open_eyes_and_hand_over_mouth:)

Actually I think CalyxOS is a very interesting project and one of the pretty good approaches to de-google a device (and there are a few other ROM projects that are also quite interesting about that topic)

If your aim is to stay away from google as much as you can for that the kraken won´t be fed with your data anymore then I personally would focus on one big step at first: Get rid of the need of having a google account (Meaning it in the way of not using/needing it anymore once you made the decision for any custom ROM)

Having a mostly de-googled device but still having the playstore (or similar google apps) on it with your google account bound to it mostly means: You fought hard fights but never ever hit the target :wink:

There are alternative app stores (Aurora for CalyxOS for example: Aurora Store) but at times that may come with some downsides - depending on how you use your device at the end.


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I use stock ROM with no Google account and de-googled to some degree manually via ADB


Ok, thank you all for your help!!! I’m going to try first calyx, and if I have trouble lineage will be my second option.

It’s funny about degoogling, I started the process about 1 year ago, but I kinda forgot? I stopped using anything related to google (search, photos, drive, email, all changed to other alternatives), but had to keep the google account for emails (in case I forgot to move anything), and that devolved into keeping it as a secondary account. I’ll use the opportunity to get rid of it for good :slight_smile:


While calyxOS is probably a good choice I just wanted to mention the #oslist in case you’re still interested in all known options you have (if you haven’t not yet stumbled upon that list).


It seems to work fine with CalyxOS, although with some small quirks.
I’ve just tested it with a Hama 00200113 USB hub + HDMI combo adapter on a 16:9 display.

Video played via VLC:

Display when locked:

Display horizontally:

Video output when oriented vertically:

(Higher resolutions available at


Thanks for the list @Volker ! I had already seen it, yes. For now I’m happy with CalyxOS, at least until one of the non android ones gets to be more… usable xD

And thank you for the pics and the info, @BjornRoesbeke . This weekend I found a dock with HDMI output that works well, but for now I’ve found the same glitches that you are reporting. Basically, when not forcing Desktop Mode, you are stuck with the native resolution (but can be changed with an app such as SecondScreen on Fdroid). When forcing desktop mode, it seems like it reserves some space on the upper portion of the screen (for the “window bar”, it seems, even when not in freeform mode), and another bit of space on the lower part (there are two buttons there, a home and a back button, both invisible but clickable).
It’s pretty wonky, and the freeform mode doesn’t work at all. Also, at least on my dock, using the HDMI output disables the USB ports, so I can only use a bluetooth keyboard and mouse…

I don’t know if all this is related to the rom or to android in general (experimental desktop mode, after all), but it’s preeeety bad. In any case, I’m happy with the phone, and I’ll use it one way or the other xD

Thank you all for your help!

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