I can connect to my MCU with the ST-Link Utility and ST-Link V2. I can perform an erase of Bank 1 and Bank 2
(Target -> Erase Bank1). I can perform an erase of all flash pages (Target -> Erase Sectors...).
However, the st-link utility fails to perform a "flash erase" (Target -> Erase Chip), I get the message "Error occured during flash mass erase!"
I tried to perform a full flash erase with Keil UV5 with the same result: I get an error, however I am able to erase individual sectors or banks.
ST-Link Utility (v18.104.22.168)
ST-Link V2 (V2.J28.S7)