Download an Android 12 or 13 GSI (Generic System Image) or a full ROM like Havoc-OS or Pixel Experience . In TWRP:
Using any other codename’s TWRP file (e.g., j7elte or on7nelteskt ) can hard-brick your phone. twrp-3.6.0-9-on7xelte.tar
Do not attempt to flash this on the original Galaxy On7 (2015) or the On7 Pro, which use different hardware platforms (codenamed on7ltechn or similar). Flashing incorrect recovery files can result in a hard brick. Download an Android 12 or 13 GSI (Generic