I left it for 2 whole hours to boot, and still the same
Are you sure you did the steps mentioned correctly? Are you using TWRP 3.1.0? Because I am using this ROM as a daily use and I had no problems. Before I publish I always take the test.
Do the Stock ROM installation again (download
here) and install with Odin (the same version mentioned).
Follow the instructions and Don't skip Steps:
1. Full wipe
2. After downloading the stock, extract the. zip
3. Enter the download mode (volume -, home and Power buttons at the same time), confirm to enter and connect the Device.
4. In the Odin pit tab, choose the file "I9100_1.5GB-System_6GB-Data_512MB-Preload_by-the.gangster.pit"
5. The AP button, choose the tar. md5 file and start the process
6. When you're done, wait for the system to Start. If you stay in bootloop, clear the Dalvik/cache by entering recovery mode and restart
7. If the system accuses that the partition is unformated, do the process.
8. Turn off the device and enter download mode again.
9. Connect the device and install the TWRP 2.8.7 via Odin by locating the file on the AP Button. When finished, your smartphone will reboot and enter TWRP.
10. Full wipe again and install TRIM + TWRP 3.1.0
11. Restart the recovery and install the latest version of the ROM.
I've done the process above more than 60 times and never went wrong.
If you can't make it anyway, try another ROM.