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$BF10:AD 41 7B * LDA $7B41 = #$AB ; $7B41 is the address of the first sprite in a level
$BF13:C9 AB * CMP #$AB ; checks if it is the sprite $AB
$BF15:D0 15 * BNE $BF2C ; if not, goes to $BF2C
$BF17:A5 15 * LDA $15 = #$6D
$BF19:29 F3 * AND #$F3
$BF1B:D0 0B * BNE $BF28
$BF1D:A9 10 * LDA #$10
$BF1F:8D FB 7C * STA $7CFB = #$00 ; $7CFB is an offset activating an already-existing flashing bg routine in the game, the value stored at it determines how long it flashes
$BF22:EE B2 7D * INC $7DB2 = #$00 ; this was to activate the sound later in the code; I couldn't directly write to any of the $4FX sounds addresses because they were zeroed after this routine before being read to play the sounds, if I remember right
$BF25:8D B5 7D * STA $7DB5 = #$10 ; $7DB5 is a custom-offset I used (replaced from a player2 related offset) to have different sets of colors for the flashing generated by $7CFB. That way in my hack there is a multicolor bg flashing & a white-grey bg flashing
$BF28:20 C0 E2 * JSR $E2C0 ; the routine I replaced (that was at $E738), placed at the end of the new routine
$BF2B:60 * RTS
$BF2C:AD 41 7B * LDA $7B41 = #$AB
$BF2F:C9 47 * CMP #$47 ; checks if it is the sprite $47 (this one activates the grey/white flashing)
$BF31:D0 F5 * BNE $BF28
$BF33:A5 15 * LDA $15 = #$6D
$BF35:29 DE * AND #$DE
$BF37:D0 EF * BNE $BF28
$BF39:A9 10 * LDA #$10
$BF3B:4C B6 BF * JMP $BFB6
(...)
$BFB6:8D FB 7C * STA $7CFB = #$00
$BFB9:EE B2 7D * INC $7DB2 = #$00
$BFBC:A9 00 * LDA #$00
$BFBE:8D B5 7D * STA $7DB5 = #$10
$BFC1:4C 25 BF * JMP $BF25

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Originally posted by never-obsolete

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well after looking at the mmc3 specs, i believe it is able to support adding more prg and chr banks. if i calculated correctly smb3 only uses half of its potential in both catagories. bank switching would allow more room to toy with and its not that difficult to do.

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