Dip Switch Settings

$B004 (Read/Write)

DS_1 value can be read from $B004. It’s being mirrored in RAM at $8013 and used accordingly. Factory DS_1 settings are: %11000000 which translates to demo sound on and upright mode.

💡 While $B004 seems like read only it actually is writable. Function at $4587 checks for two player game and when the mode is set to cocktail it writes 1 to flip the screen for player two and 0 back for player one.

$B005 (Read Only)

DS_2 value can be read from $B005. It’s being mirrored in RAM at $8014 and used accordingly. Factory defaults for DS_2 are: %01010000 which translates to high special coin ratio, hard difficulty and bird moving fast.

💡 On the contrary to DS_1 it is read only however it holds its own secret. According to manual, first three bits / switches are unused and should be turned off. But if you enable function at $5A07 by replacing $C9 (ret) with $F5 (push af) you’ll get access to unused “Extra lives” setting.