We are using the STM32F051 series and have been experimenting with the flash memory protection. We have successfully protected some devices to level 1 i.e. set the RDP option byte to a value that neither 0xAA or 0xCC. However we now seem to have 'bricked' these devices! However my understanding is we should be able to go in and change this byte back to 0xAA which will erase the memory but at least we can then use the devices again. However we cannot gain access via the Keil ST-Link debugger. My question is - how do we recover these devices?