In case it helps, e-Recovery will look and behave like this [HOWTO] use e-Recovery to wipe & format data before sideloading/install eOS.
It seems that the OTA upgrade of Samsung S7 does not appear on the “announced list” Edit The OTA Android version upgrade of Samsung S7 to Android 12 (S) was announced quite recently, you can check in this section for information.
However the OTA Upgrade is or was in Testing – it is a possibility (??) that you gave your phone access to the Testing servers in Developer options like this
- Settings > System > Advanced > Developer Options
- Scroll down to the end of the screen
- Enable the option
Connect to /e/OS test channel
The Testing session [S7/S7+] Test session to OTA upgrade from 2.1-r to 2.2-beta-4-s (#73) · Issues · e / QA / Testing Community · GitLab was closed a week ago, so maybe it was quietly released, idk.
The OTA upgrade is only designed for Android 11 (R) to 12 (S), so this will be part of the reason for failure. Only stable builds get OTA upgrade; for other builds the Upgrade path from Android 10 (Q) is to treat the upgrade virtually as a new install Install /e/OS on a Samsung Galaxy S7 - “herolte” and include Format data.
I suggest that if you can possibly replicate the Q → R upgrade you might be able to remain on the stable channel and (possibly) not have to Format data.
To do this you would aim to use heimdall to install e-Recovery recovery-e-1.17.1-q-20240208379201-stable-herolte.img then adb sideload e-1.17.1-q-20240208379201-stable-herolte.zip
The phone may tell you that this is a downgrade and refuse. I would have a go in the hope of avoiding Format data, if that was an issue.
Edit There is a stage two to this suggestion. You might have to avoid having the phone attempting the R → S Upgrade again while you check that the Q build is functional. Then use heimdall to install recovery-e-1.20-r-20240221382013-stable-herolte.img and then adb sideload e-1.20-r-20240221382013-stable-herolte.zip. Now on Android (R) you could wait (and test the build) to see if OTA Upgrade commences “normal service”.
However after the problem you have experienced you might be better advised to make a “Clean start”.
I think that if you take a different approach and update your recovery to match your (assumed) current e-2.2-s-20240716417774-stable-herolte, that is recovery-e-2.2-s-20240716417774-stable-herolte.img from /e/OS stable herolte download you will almost certainly have to Format data.
Your PC, you mentioned Mac, maybe you could borrow / get access to a Linux machine, will need Heimdall – OSX is mentioned here https://raw.githubusercontent.com/Benjamin-Dobell/Heimdall/master/OSX/README.txt there is also heimdall.dmg and a walkthough on the forum How I managed to install /e/ on a Samsung A310F with MacOs 10.13.6.
You also need platform tools, available for Mac, SDK Platform Tools release notes | Android Studio | Android Developers.
I realise that the install page may look a bit intimidating, feel free to ask anywhere it is not clear. This particular page is complicated by Windows instructions so you need to be quite single minded about what OS you are using.