# NES roms question



## Panja (Dec 17, 2014)

I'm have a question about the NES roms "floating" around.
Most of them have only 1 release but a few others are marked _Rev A_.
What are the differences between a "normal" release and a Rev A release?
Which one should I take?

For instance:
Castlevania (USA) vs Castlevania (USA) (Rev A)
Super Mario Bros. 2 (USA) vs Super Mario Bros. 2 (USA) (Rev A)
Super Mario Bros. 3 (USA) vs Super Mario Bros. 3 (USA) (Rev A)


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## ShadowOne333 (Dec 17, 2014)

Rev A in ROMs denotes that the version of the ROM is an updated revision from the original release.
Let's say the original ROM had some typos, Rev A fixes those typos or fixes some glitches.

Same goes for Rev B and so on.


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## reprep (Dec 17, 2014)

Keep in mind that Rev A and Rev B might contain censors/modifications too. So it isn't always the  best choice to go for the latest revision.


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## ShadowOne333 (Dec 17, 2014)

^One clear example of what reprep says is the Revs for Ocarina of Time.
The original ROM had a chanting in the Fire Temple, Ganondorf's blood color being red, and some other muslim references (Moon symbol on the MIrror Shield i.e.) that posterior revisions (Rev A, Rev B) changed to avoid controversy.


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## Panja (Dec 17, 2014)

Thanks for the clarification guys!


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## Mark McDonut (Dec 17, 2014)

also worth noting, anything bracketed are known as GOODCodes, so in a case like that, a lowercase bracketed a means it's an alternate version, however a lowercase bracketed b will actually mean it's a bad dump, go for the one that has a bracketed ! if you want a working rom.

example:

Adventure Island [.b].nes is a bad dump and will probably freeze, crash or behave odd (ignore the first period, this site uses brackets for page formatting and it keeps bolding everything)
Adventure Island [a].nes probably works ok and may apply to the above posts in regards to being newer
Adventure Island [!].nes is verified as a clean rom with no patches, modifications, or hacks.


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## Panja (Dec 17, 2014)

I've been using the NO-INTRO sets for all my roms (using RomCenter) and not the GOOD sets.
So I don't think this goes with my sets right?


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