Error reading flash config area after programming 0x7F in FOPT

[jernst]

I have a problem verifying flash config area on a S32K116 controller.
Erase values are 0xFF in the flash configuration area 0x400-0x40F except FSEC which is 0xFE.

Writing and reading works with the above values after mass erase.
But when I use the image file which defines 0x7F in the FOPT register then it doesn't work.
Writing is okay, but verifying can read all other memory adresses except area 0x408-0x40F.
I got an access fault via JTAG/SWD read. When I run a programm on the chip and then read an address in that area the program stops, too. Probably it performs an exception I couldn't check.

In the reference manual it says "Reserved for future expansion" about bit 7 in FOPT register. And at other places it says "Refer to the device's Chip Configuration details for the definition and use of these bits." I couldn't find these definitions. In which manual is it?
What is it with this value 0x7F in FOPT register which locks read access to the flash area 0x408-0x40F?

How do I solve this problem?

[jorge_a_vazquez]

Hi Juergen Ernst

The bits in the FOPT register should not affect the read-write of the memory, those bits are reserved and in functionality, of the s32k device, they don't do anything. Could you clarify how are you performing the register read? I'm using S32DS and I'm able to read that location even with the bits set as 7F:

Regards

Jorge Alcala