According to the SNES manual, for HiROM, the cartridge SRAM is located in banks 0x30 to 0x3F, offset 0x6000 to 0x7FFF. This implies BA4 and 5 are 1, BA6 is 0, A13 and 14 are 1, and A15 is 0.

But the MAD-1 chip doesn't have any connection to BA4 at all, making the banks for SRAM go from 0x20 to 0x3F.

Does the SNES care if the SRAM is active during that memory region, and if so, why? Thanks for the help!

I'm curious why the questions. Are you trying to understand the MAD1 chip?

Nesdev might be a better forum for this question.

I'm working on my own SNES boards (I've got a few ideas I want to implement that I haven't seen anywhere else) so I'm figuring out the wiring for the LS139 decoder for HiROM. Since I've seen a lot of other sources say that mapping the RAM starting at 0x20 instead of 0x30 works (and confirming the wiring with a HiROM board that uses an LS139), right now I'm just making the boards like that. But I'd really like to understand why. Not sure if anyone knows the answer or not though!

Along with making the boards, I also want to detail the entire workings of the board on my website, a topic I've been hard-pressed to find in-depth explanations on.

I'll pose the question over on NesDev as well.