The Code Security Module Documentation has two statements:
1- "Do not use 128 bits of all zeros as the password. This automatically secures the device, regardless of the contents of the KEY register. The device is not debuggable nor reprogrammable."
2- "If a device is reset while the password locations are all zero or an unknown value, the device will be permanently locked unless a method to run the flash erase routine from secure SARAM is embedded into the flash or OTP."
Does this mean that, even though the 128 bits password are all zeros, a "dedicated" bootloader programmed on flash and running on secure SARAM can still reprogramm the flash ?
Is my understanding right ?Thank you for your attention.
Yes. If the passwords are unknown or all 0x0000, and you already have the flash erase API routine programmed in flash and have a way to get the code to execute it properly (i.e., copy to RAM and run from there), it can erase the flash along with the unknown or 0x0000 passwords.
Regards,
David
-----------------------------David M. AlterSenior Member Technical StaffTexas Instruments Inc.