So as Nougat is getting quite old, I tried myself at building Pi/e/ for I9100 and to my surprise it built quite easy and succesful, thanks to rinando and linusdan a.k.a Danilo Santos ☭.
To flash it please follow the steps given at this XDA-page by Danilo, as this device is quite old and it is not intended for such new android versions you have to follow the exact steps for flashing;
Boot your phone into Download-mode (Volume down + Power/Standby + Home and hold for 10 seconds).
Start ODIN 3.07 on your PC.
Connect your phone via USB to your PC.
Press volume up on your phone, ODIN should detect your phone.
Auto Reboot : unchecked
PIT : i9100-LOS-16.0-Emulated-Storage.pit
PDA : i9100-LOS-16.0-Emulated-Storage-TWRP-3.3.1-1.tar.md5
After succesful flash, reboot phone into Recovery:
Press Volume up + Power/Standby + Home and hold for 10 seconds.
The phone shuts down.
Repeat Press Volume up + Power/Standby + Home and hold for 10 seconds
Phone boots in recovery TWRP 3.3.1-1.
Swipe to Allow Modifications
In TWRP 3.3.1-1 you need to format partions
Wipe -> Format Data -> Type [yes]
Wipe -> Advanced Wipe -> Select:
Davik / ART Cache
-> Swipe to Wipe
the first boot may take several minutes to start, be patient.
Please note this is a test build.
Please take a backup of your data before your proceed.
Please report if you encounter bugs.
If you are Ok with these warnings then you can download the Pi/e/ image for the Samsung Galaxy SII - (i9100) “i9100” is available for download here
for Heimdall flash please use the same files as given in the linked XDA thread and follow these steps:
i m on linux since years now and always had good experiences with heimdall :)) it may be a little bit more complicated for new users… In this case i just copy pasted from xda LOS 16.0 thread for i9100…
@breversa You have the BOOT.IMG inside the ZIP of the /e/ROM. You copy this BOOT.IMG to your smarthphone’s memory. Then, you have to install Magisk Manager (APK), and from it install Magisk by choosing the option to patch BOOT.IMG. Select the BOOT.IMG you found in the ZIP from /e/OS. When Magisk Manager is finished, it will have created a magisk_patched.img inside the Downloads folder.
You already have your BOOT patched with Magisk. Then if you want, you flash it to have root.
I am not sure, but I had the same issue after flashing with adb sideload. I waited more than 1h for the first booting. I forgot, that there was an SD plugged in. I removed the SD and flashed the phone again. After flashing without SD, my i9100 booted successfully. I think it took 20 minutes for the first boot. Maybe it does not work with an SD-Card plugged in. After the first successful boot, I plugged the SD-Card in. The SD was successfully detected, formatted and worked.