CubeProgrammer reads suspicious addresses on the stm32u031

[eay]

CubeProgrammer is reading from some suspicious addresses on the stm32u031.
For example, sector erase from the GUI:

09:24:20:751 : r ap 0 @0x1FFF37FE 0x00000001 bytes Data 0xFFFFFFB1
09:24:20:755 : Flash sector erase ...
09:24:20:755 : r ap 0 @0x40022040 0x00000004 bytes Data 0x00000000
09:24:20:755 : Flash erase...

and from the CLI:
...
r ap 0 @0x1FFF777C 0x00000004 bytes Data 0x00000000
...
Erase sector(s) ...
r ap 0 @0x40022040 0x00000004 bytes Data 0x00000000
Flash erase...

0x40022040 is offset 0x40 into the FLASH block which is labelled as reserved in RM0503 3.7.22 Table 19.

0x1FFF37FE and 0x1FFF777C are high in the option bytes block.

[Danielhtomas]

Interesting observation. Those addresses do look unusual at first, but CubeProgrammer often accesses reserved or undocumented regions for internal checks, device identification, or flash operation handling.

The reads around the option bytes and FLASH registers might be part of its verification or safety mechanisms rather than actual user-level operations. Still, it would be good to confirm with ST documentation or support whether these accesses are expected behavior for the STM32U0 series.