SDB ROM: commit_id is stored with nibbles reversed
The commit_id field in the SDB synthesis record is stored with each pair of byte nibbles reversed.
Example: 0xd8 is stored as 0x8d
This is due to a bug in the f_string2bits() which takes the commit ID as a string argument, assuming that the character array of the string is (32 downto 1), while in fact the commit_id is a string(1 to 32).
f_string2bits() should be made more resilient, and work with both "up" and "downto" string arguments.