First of all go
HERE and you'll get links to the firmware, make sure to check the version of your motherboard first. It also tells you how to check on that page, but basically it's removing the battery cover and battery.
Though as you have a 2.1 board,
this firmware supports all board revisions except for the Plus boards.
Once you've done that and downloaded the correct firmware, unzip it to your hard drive. No. matter what other files there are there will be one called RetroFW.img or something similar, the .img part is the giveaway.
Download Etcher for your Mac from
HERE and drag it to your Applications folder.
Insert the Micro SD card you want to use into your Mac and launch Etcher.
Now drag the RetroFW.img onto Etcher and click on Select Drive.
Make sure you select your Micro SD card or you'll f*ck something up, be very careful here.
Now just click on Flash and wait for it to finish.
Remove the Micro SD card, put it in your RS-97, switch it on and wait for it to finish it's setup routine. It will probably restart when it's finished.
Once it reboots there will probably only be two icons (maybe not, depends on the FW you chose) but if there is, head on over to this
Github Page (same as the firmware one I linked) and scroll down until you see the emulators.... pick whichever ones you want and transfer them to your Micro SD card.
Use the Explorer app on the RS-97 to install the emulators and you're good to go.
Think that about covers it.
