“It is a microscopic logic gate that is electrically switched from ‘0’ to ‘1’. Once it is switched, it effectively ‘burns the bridge’ to allow older software to run.”
OnePlus silently pushed an update that permanently fuses your phone’s processor to reject older firmware. Try to downgrade or install a custom ROM and your phone becomes a brick. Not a soft brick. A hard brick. The only fix is a new motherboard. OnePlus won’t even acknowledge they did it. You paid for the hardware but they own it. This is what “security” means now: locking you out of the device you bought so you can never escape their software.