I copied the FRAM. I have used an Arduino UNO with level shifter. The trial period is probably stored at 0x7F6 and 0x7F7. There seems to be no checksum.
could u also check if u see any matching between your serial number, and values in the FRAM ?
the code makes use of a string reference of:
SDRAM:EFFD94 aDs2a0000000001:ascii "DS2A0000000001",0 # DATA XREF: sub_10C700+48?
my guess would be: DS2A0000000001 + some FRAM value = the serial
and the serial determines the bandwidth limit ...