NintendoAge http://nintendoage.com/forum/ -Sqooner Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-23T17:58:43 -05.00 A2600 29
"Looking at Bananmos' verlog, it looks like it supports 1-screen and 4-screen but the assignments are backwards, unfortunately. So, if you have a hex editor, you can change a single bit in the ROM to make it work with the backwards assignment. Byte $6 (the 7th byte) of the iNES ROM should be $E8. Change it to $E9 and it should work."

And lo and behold, it does!

Load the Twin Dragons ROM into a hex editor and the first eight bytes read thusly:

4E45531A 2000E810

Change the 7th byte from E8 to E9 so that you have:

4E45531A 2000E910

Save the file, load onto your PowerPak, and presto! It now works using Bananmos's Mapper 30. All you PowerPakkers may now buy the ROM with confidence; it just needs a quick edit! ]]> Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-18T19:24:05 -05.00 A2600 29 Originally posted by: glutock

Yeah but depending on when you bought the game you could have v191 or v192. If you have v192, please download the game again to get v191 since v192 has a header issue.
I bought it last week on Tuesday February 12th.  Can't check which version I have at the moment.
  ]]> Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-18T16:46:08 -05.00 A2600 29 Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-18T16:43:35 -05.00 A2600 29 Originally posted by: glutock

@WaverBoy : which ROM version are you using? The one for sale here:

https://www.brokestudio.fr/en/shop/twin-dragons-2/
  ]]> Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-18T15:38:09 -05.00 A2600 29 Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-18T15:33:04 -05.00 A2600 29 Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-18T15:16:24 -05.00 A2600 29 Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-13T15:13:40 -05.00 A2600 29   ]]> Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-13T14:48:05 -05.00 A2600 29   ]]> Problem Getting Twin Dragons To Play on Everdrive http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=185618 2019-02-13T14:29:44 -05.00 A2600 29 Originally posted by: glutock

For the PowerPak, please download the file in this thread : https://forums.nesdev.com/viewtop....
And copy/paste the .MAP file on your PowerPak CompactFlash card.

It should do the trick (I don't have a PowerPak myself). Looks like it's Mapper 30 by Bananmos (his "Toy Project" linked to in his post on that thread) that does the trick; NovaSquirrel's Mapper 30 apparently doesn't work properly with Twin Dragons.

Thank you so much for pointing me in the right direction! ]]>