otp.bin
If your Wii U suffers a "brick" (a software failure that prevents booting), these files are necessary for recovery tools like the Nintendo Wii U Recovery Menu to access and repair the system memory. otp.bin seeprom.bin
Security researchers analyze otp.bin for hardware backdoors. For example, some Chinese IoT devices have had secret "master keys" discovered inside OTP dumps. otp.bin seeprom.bin