Why would you write the current time in the FLASH? It would be out of date pretty quickly... The copy of the ACPI variables in RAM are updated all the time, as needed, but it is not my point.
What I noticed is that the FLASH CRC32 was switching in between two values, then I tried to limit the FLASH checkuming part to what is visible (real-mode address 0xE000:0000 to 0xFFFF:0000) but it did not work neither.