forge + push (see build.sh); host python3:
python3 forge_df5784.py base.img craftA.img craftB.img
[walk] pfs_blk+1: type=4 key=0xdabac95413ee8001 keybits=0 doff=0x0
[forge B] DIRENT key -> 0xc000000000000001 keybits -> 63 @0x1800a80
FORGE_OK