Yamaha SRE-01 - 32K RAM/Expansion Slot Unit can be upgrade?

On which machine do you want to use it?

To upgrade beyond 64kB, it needs to be a memory mapper (and upgrading it to 64kB would NOT give you an additional 64kB as it would overlap with the base memory in the system) And since you intend to use this on MSX1 systems, it needs to be a self-initialising memory mapper. So the answer realistically is NO you cannot.

Have a look here: https://www.msx.org/wiki/Category:RAM_Expansions

You can use this adapter for the ax100: (Ask to Alexey)

https://msx.org/news/hardware/en/cartridge-adapter-for-yamah...

and an MMM for all: (ebay)

https://www.msx.org/wiki/Popolon_Musical_Memory_Mapper

Question is: what do you need more RAM for? The AX-230 and AX-170 already have 64K which is a good spec for an MSX1, and the AX-100 is also 64K if you insert the RAM expansion... You can use some larger memory mappers in MSX1 computers but few software use it.

Relatively speaking it’s few. None of the commercial MSX1 software from the 80s require more memory. It is not common to need more than 64K for an MSX1 unless it’s relatively advanced usage with e.g. a modern all-in-one Nextor cartridge (but they already have extra memory so that’s probably not it).

I ask amerklm22 what he needs more RAM for, because a memory mapper may not be the solution for his problem, or there may be a better alternative solution. It would be a shame if he buys a memory mapper like you suggested and it turns out to be a waste of money because it doesn’t solve the problem.

If he wants to use DOS2 on MSX1 for example then he should get a SD/CF interface with Nextor and extra memory. If he wants to play cracked MegaROM games he may be better off with a FlashROM or MegaRAM cartridge. I’ve also seen posts in the past thinking that more memory will increase the speed of their MSX, just like it used to on early Windows PCs.