Finally, Super Mario Bros. NES european Revision A now receives an unofficial revision, which is called Revision B. This revision contains further bugfixes, improvements, and a few differences. Here they are:

  • The Lakitu now throws the Spiny Egg correctly.
  • Mario and Luigi have separated fire color palette.
  • Except Bowser and the mountain graphic, all the green-colored enemies/items/graphics have darker green color.
  • After having more than 9 lives, the counter shows the actual hexadecimal values.
  • The edge of the cloud/bush is now fully filled with black line.
  • Between ‘THANK YOU’ and ‘MARIO!’ (or ‘LUIGI!’) there is now a comma.
  • The exclamation mark and the dot has been resized.
  • The original game over music is now replaced with the unused alternative one.
  • The musics and the sounds have their original speed again.
  • The coin’s sound is different.
  • The coin’s counter has 3 digits.
  • The “x” graphic at the coin counter has been moved up a little bit.

Thanks for Eden GT for his techincal helps. Thanks for 4matsy for the ASM code that separated Mario’s and Luigi’s fire color palette. Thanks for doppelganger for disassembling SMB NES. Thanks for MrWint for disassembling the PAL version. Thanks for SpiderDave for converting the source code.
What else to say? Enjoy!

https://www.romhacking.net/hacks/4424/