Seeking Effective Flash Protection Methods for 54L05 Chip

[Ozzy]

Hello everyone,

I am currently working on implementing the flash protection feature for the 54L05 chip. My objective is to safeguard the code storage area from unintended erasure or overwriting during program execution. I have attempted to use the fprotect_area function for this purpose. However, upon verification, I found that the protected area can still be erased or written to. Could anyone share some ideas or alternative solutions to achieve effective flash protection?

P.S. The SDK version I am using is 3.0.0.

Thank you in advance for your valuable input!

[Susheel Nuguru]

Sorry for late reply. The pro_len size is clearly wrong as 0x1000 = 4096 and multiplied by 400 gives you about 1.6 MB and you do not have this much storage in nRF54L05. As mentioned here, you have only 0.5MB of storage on this SoC so max value you can use on pro_len is (0x80000)

[Ozzy]

Hi, thanks for your reply!

As soon as I read your response, I immediately spotted the mistake in my code and made the necessary corrections. However, the outcome is still not satisfactory. I set the length to (0x1000*0x80), but it still returns an error code of -22. After verification, I found that the code only works effectively when the length (pro_len) is less than or equal to (0x1000*0x07).

Looking forward to your reply!
Ozzy

#define pro_len (0x1000 *0x80) 
/*
To ensure the operation is successful, 
the value of this macro definition needs
to be less than or equal to 0x7000.
*/
void flash_test(void)
{
	printf("Lock 0x%x from 0\n",pro_len);
	errno = fprotect_area(0x0000, pro_len);
	if (errno) {
		printf("Failed lock err %d\n", errno);
	}
	else{
		printf("Lock ok\n");
	}
}