I'd much rather see the code - if possible. By not submitting stale shares, this firmware shouldn't be used with p2pool - you're losing potential blocks. This was fixed with kano's binary here:
http://ck.kolivas.org/apps/cgminer/antminer/s5/
Unfortunately, it is not persistent through reboots
You can trust Ck and Kano firmware they write most of the cgminer releases any way. There great