I've used a sawzall.
Clean the sawzall really well with dish washing detergent and then wipe down with rubbing alcohol. Take small trash bag or freezer bag and insert over blade end of saw. Cut slit in bag just big enuff to fit blade thru when mounting blade to saw.
Puchase new blade(s) and clean as above. Insert blade in saw.
Helper holds frozen belly with hands safely out of the way while belly is cut with saw. I found this to not even a 1 beer job. The other end of the spectrum would call this a 6 beer job, meaning you could drink up to 6 beers with no fear of being able to not complete the task.
Keep those fingers and hands safe tho folks.
I don't have too much trouble cutting frozen pieces of belly or backfat. Get a heavy knife, make sure it's sharp and proceed carefully. A bandsaw is not necessary. I typically just place it to the meat and with both hands press down as if I was slicing a major hunk of cheese. No hacking, no sawing.