Samsung Galaxy S9: When revert to Stock ROM went wrong (but happy ending)

Hi everyone, here a little story/guide/workaround from a newbie who goes trough big mistake, when you decide to revert on STOCK ROM (for whatever reason, mine was for upgrading the Android version from 8 to 10 based on my /e/device that i converted long time ago with a dev branch not longer maintained today )

Here the thing.
Because of my /e/OS version not maintained and the release of the V1, i decide to upgrade my phone.
But to do it, i wasn’t able just to upgrade. I was on a Android 8 version and would to go on 10 (last android version available for my S9 as far i know) and in my understanding, i was forced to go back on a stock ROM, upgrade to 10 and then go back on /e/.

I go on the documentation of my S9 and find a step by step guide to revert the /e/device on a stock ROM.


The documentation mention the Sammobile site to get the stock ROM, or you need an account to download. Fair enough. BUT (again !), you need an premium (so paid) account to get older firmware (ROM) than the last available for your model device (and mine was on 10…)

Here the situation. I’ve got an Android 8 version, can’t revert on a 8 stock version. Just got a 10 version.
I’m not very acknowledge about Android and all the stuff, so i just follow the guide. But with my android 10 version.

i’m also on Linux, so forget about Odin (not working with Wine, and i wasn’t also able to do it trough a Windows VM). I used heimdall (which was never an issue in any way) with the help of some thread find on the web (on XDA Forum, mostly)

I flashed my phone with the Android 10 ROM trough heimdall (with a front-end, not on CLI)
It worked !
And the problems begins !

My phone was on a loop at boot. But i was able to go on Download mode or in the recovery (the factory one, i was on TWRP, but my flash wipe it out).

So the phone wasn’t brick and hope was still there.

As i said, i’m not, in any way, familiar with android (i was a iOS user before /e/).
I was desperate with the situation and didn’t know what to do with it. The log accessible in the phone just mention “boot on recovery for reason : UNKNOWN”
So i decide to really try to flash an Android 8. I finally find a ROM for the 8 version (on

But it was impossible to flash. As i find Samsung doesn’t allow downgrade…
My previous flash obviously change the thing and give me no choice about a downgrade to 8 anymore…
Again, don’t know what to do but the phone was still able to go recovery or download mode …
In this stuck situation, thinking my phone was kind of lost, i just decide to try to install /e/.

The easy-installer wasn’t able to identify my phone anymore and i discover i can’t use adb to sideload files on my phone nor used the SDcard… Aaaargh ! Great !
So, i decide to just flash the recovery (like said in the guide ) and boot on it. It worked. I look around and find options to installed with SDcard. And i was able to do it ! The factory recovery was’t able to do it, but the /e/ recovery yes.
Then i upload all the files on the SDcard (patches and /e/OS) and do all the stuff trough the /e/ recovery.

And it work perfectly !
I’m now a user of the V1.2 /e/OS on my old Samsung Galaxy S9.
As far i can tell, everything work perfectly.

In summery :
Use the site, not the Sammobile site (like mentioned in the guide !!!) to get the older ROM you need.
Don’t jump version of Android !
If you do, just flash the /e/recovery on your phone and work form a SDcard trough it.

Hope this will help some others. If needed, maybe i can try to write a step by step guide for Linux user with Heimdall. (It require more steps than using Odin in Windows).

So sorry for the loooooooong message (i’m not that good in english, so it’s longer for me to explain my thaughts)

Cheers !

Very interesting sharing.

But it seems to me that you don’t have to go back to stock Android to upgrade your Android /e/ OS version. (at least not for the vast majority of devices).

A reinstallation via recovery does the trick.

Going back to the original stock ROM is however necessary to downgrade

As for the S9, a direct OTA upgrade will soon be available on /e/, so there won’t even be a need to reinstall the ROM via Recovery: