Does your FS26 do a valid OTP operation?or you can show the FS26 full part number here.
If no ,you can do OTP to change this bit by NXP programmer socket board, if already done OTP, you can't change this bit anymore by SPI.
KITFS26SKTEVM FS26 Safety SBC Programming Socket Board | NXP Semiconductors
the full part num: FS2613AMDA3AD,
the chip is welded to our board. It is a new chip. So we want to OTP program.
We don't have the KITFS26SKTEVM, we just want to use MCU to program it.
the main register is 16 bis while the otp register is 8 bit. What the difference in spi?