Can I reset the device without clearing memory contents?
Please be noted that SRAM must be initialized after power on reset anyway. Because the ECC bits can contain random data after the device is powered on, the SRAM must be initialized by executing 32-bit write operations prior to any read accesses. As ECC checks are performed during the read portion of an SRAM ECC read/write (R/W) operation, and ECC calculations are performed during the write portion of a R/W operation.
(extracted from ST Online Support Service)