Chosen Solution

Hi everyone, I’ve replaced the ALS/earpiece flex on an iPhone X and the true tone function no longer works. The original screen is still fitted, only the ALS flex was replaced as the earpiece wasn’t working. could this be because I’ve used a cheap 3rd party flex as opposed to a genuine one? Or is it another security feature by Apple alike to the one with screen replacements? thanks in advance

Security feature is usually the answer. “True” tone requires display and ALS calibration data, if you swapped the ALS without doing re-calibration, then “True” tone is no longer “True”.