The PSP Go was Sony’s digital-only entry into their PSP lineup. It featured a smaller form factor, Bluetooth integration, but also, the removal of the UMD drive. This meant that all games needed to be stored on it’s internal 16GB of memory or on an M2 Memory Stick, which is a proprietary storage format developed by Sony.
Instead of using the more widely available SD card, Sony tried to push their proprietary format. They would eventually abandoned the format in favor of using the more ubiquitous SD card standard, but this changeover was too late for a lot of Sony devices, the PSP included. Sony’s M2 Memory Stick unfortunately maxed out at 16GB before being discontinued, meaning that if you were fortunately to have one of these larger cards, you could only expand the PSP Go to a total combined amount of 32GB (internal 16GB + 16GB M2 Memory Stick). While that may seem like a lot, you have to understand that PSP games are rather large, ranging anywhere from a few hundred megabytes, all the way to nearly 2 gigabytes per game.
With the discontinuation of their Memory Stick format, that meant capacities larger than 16GB never were manufactured. So it would seem that the PSP Go would be maxed out at 32GB forever.
Well, that was until a Japanese modder by the name of @Kouchan66 created an internal Memory Stick to microSD Card adaptor for the console.
This kit interfaces with the M2 port and allows you to connect a microSD card up to 128GB in size, greatly expanding the consoles capacity and the amount of games you can install onto it.
Unfortunately, @kouchan66 stopped selling these kits back in 2019, However, since then a few vendors have replicated the mod with their own iterative improvements. One such modder is Genius Game Mods.
Now there are a few shortcomings of doing this mod. One of them being that in order to install it, you do need to trim some internal plastic tabs to create room for the adaptor due to the PSP Go’s densely packed internal layout. Additionally, again because of the limited space, the adaptor will cause a very slight bulge in the rear shell due to there being just barely enough space for the mod. It’s pretty unnoticeable, but it is there. I outline and showcase all these in my video linked above.
Other than that, I would consider this to be a must do mod for the PSP Go since, as a digital-only device, storage capacity is of utmost importance to get the most out of it.
