Screen replacement with transplanted touch ic

Hi,

Recently purchased an iphone 12 with a bad lcd (screen was only working when applying pressure on it). Went online and ordered a new aftermarket oled from china. The new oled screen came without the touch ic, which made the repair easier as I didn't have to grind the new ic off. So I removed the original ic from the old damaged screen (which was working before the repair), reballed it and soldered it on the new screen. All good so far, but when I fitted the screen, the phone wouldn't boot, it would just shiw the apple logo for a 4-5 seconds then go off, repeatedly, in other words, stuck in a boot loop. Have tried all the "7 ways to fix apple boot loop" methods, with no success. If I remove the ic, the phone boots fine, but shows the dreaded 'non-genuine display' message.

Has anyone else seen this, could it be the oled from china that's dodgy, or could have I burned the ic while transplanting it?

Thank you!