I've got a question about the OnePlus X. While I realize the main discussion is happening here

https://forum.xda-developers.com/one...sh-os-t3322567

I wonder if someone of you could give me some info.

It's about that mysterious "different" version of the Onyx which rinigus mentions here:

https://forum.xda-developers.com/sho...postcount=1007

To test I was contemplating buying a used OnePlus X here in Europe (from Amazon or Ebay). Is there any way to be sure it won't be the "wrong version"?

Background: While I totally love my Nexus 5, not being able to make phone calls with bluetooth does not really help. So, I was just thinking...

look for specific information regarding incompatible builds in that thread as well as https://forum.xda-developers.com/one...orage-t3513748 . I don't remember specifics anymore, so you would have to look them up.

Thank you so much for your quick help, rinigus. So, I read the entire thread (wow, what an onslaught of frustration has been accumulated there) with the very last message mentioning the impossibility of installing SFOS. Too bad really. So, I guess the Onyx is not for me. I'll keep on looking for another non-Sony phone.

Again, thanks for your help!

All you need is the older bootloader, if you get a "nee" X, here is how to downgrade to older bootloader (for installing TWRP, CM12 and, SailfishOS which requires old bootloader.

https://forum.xda-developers.com/sho...3&postcount=45

Thanks a lot for the uplifting advice. I really do appreciate that quick response. I'm curious, do you have one of those version 15 Onyxes yourself?

Probably flashing is only half as bad as it is in my imagination. But all the information I read is very confusing (for someone who certainly hasn't had much to do with the Android world apart from flashing the Nexus 5), since it's always bits and pieces, never a straight step by step process from "unboxing right through to booting into SFOS".

For example, the instructions in the link you provided state that after downloading the zip and the specific twrp, one is to "Boot into recovery, first flash the oos2.2.1-x.zip". I have no idea how to imagine that step. Is that some Onyx stock recovery? If so, where can I find a step by step guide?
At what point does one install twrp?
And will this twrp-3.0.2-0-onyx.img definitely work on the version 15 onyx?

At https://wiki.merproject.org/wiki/Ada...Pre-requisites I read about a specific OnePlus X ROM and a particular twrp one is to use, both of which seem to be different from the ones in the other post. So, I wonder how they would interact with SFOS.

In summary, this still seems like a rather large risk to me. After all, I don't want to buy and brick the phone within only a few minutes.

Yes, since you will be downgrading, its necessary to boot into recovery twice.

No full reboots between the flashing.

1. First flash TWRP for the NEW bootloader (download the LATEST version from twrp.me)

2. Boot to TWRP

3. Now, flash OnePlusXExtraPartitions-2.2.1-X-0.zip https://forum.xda-developers.com/dev...t/dl/?id=18431

4. flash the OLDER TWRP! https://dl.twrp.me/onyx/twrp-3.0.2-0-onyx.img

6. reboot to the just flashed TWRP (reboot recovery from TWRP)

7. Then, flash CM12.1 and after that the SFOS (as described on wiki)

Be re-assured that providing you ensure that you have working fastboot & ADB installed upon PC, it is almost impossible to "brick" such Android device; that said it is always more difficult being a late adopter as too many referred to links become "404"with passage of time. Usually all that is needed is to place .zip upon root of SDCard for it to be visible from recovery, although suggest TWRP be installed earlier rather than later.

Whilst Amazon is your preferred choice here is one which would just need your Jolla account to go and I'm sure other users would vouch for condition of my device(s) offered on forum previously.

I also confirm that downgrading to an older bootloader via TWRP and then flashing Sailfish via the older TWRP did the job for me about 2 years ago. I don't remember the details, but it was more-or-less straightforward (/me also not Android guru)

So, my order has been placed (so, I'm jumping into the deep end) and while I am awaiting delivery I am trying to get everything prepared - well, as far as I possibly can.

@nieldk, I am so grateful for your step-by-step description. It really cleared u a lot of things for me

May I still ask a few stupid questions?

Is the oos2.2.1-x.zip you mentioned identical with the OnePlusXExtraPartitions-2.2.1-X-0.zip I downloaded from https://forum.xda-developers.com/sho...91&postcount=1 (I got there through the link you provided - https://forum.xda-developers.com/sho...91&postcount=1 )? I know it probably is the one you meant. But I just want to be absolutely sure not to cause damage by accidentally having picked the wrong file.

For step 5 do I use the TWRP version linked to from the merprojects wiki https://forum.xda-developers.com/dev...t/dl/?id=15644 or the one from the general instructions here https://forum.xda-developers.com/sho...3&postcount=45 ?

Do I need to adjust any settings in TWRP at any point, like erasing parts?

@dubliner: I would suggest to wait till you get the device and check the build number. Maybe yours will work out of the box?

Next, you may want to get SD card. Onyx is blessed with having a slot for it - its great to keep your photos, videos, and other larger files. In addition, it allows you to make a snapshot of your internal storage and restore it later with TWRP. For reference, I use 64GB card - 20 GB is used right now (2 backup, photos/videos, maps).

Cannot help with the other questions, unfortunately.