Disclosed is a power isolation and backup system. When a power fail condition is detected, temporary storage is flushed to an SDRAM. After the flush, interfaces are halted, and power is removed from most of the chip except the SDRAM subsystem. The SDRAM subsystem copies data from an SDRAM to a flash memory. On the way, the data may be encrypted, and/or a data integrity signature calculated. If an error is detected, a data integrity signature may be corrupted. A completion signature may be written. To restore data, the SDRAM subsystem copies data from the flash memory to the SDRAM. On the way, the data being restored may be decrypted, and/or a data integrity signature and completion signature checked.