INES Mapper 177

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iNES Mapper 177 is used for games from 恒格电子 (Hénggé Diànzǐ). It's basically oversize BNROM without bus conflicts, with an additional mirroring control, and with 8 KiB of battery-backed WRAM at CPU $6000-$7FFF.

            7  bit  0
$8000-FFFF: ..MP PPPP
              |+-++++- Select 32 KiB PRG-ROM bank at CPU $8000-$FFFF
              +------- Select nametable mirroring
                       0: Vertical
                       1: Horizontal

Some Hengedianzi games use hard-wired mirroring and do not set the M bit correctly; they are set to INES Mapper 241 instead.