How to work with SD card partition?

[Flavor]

It actually came like that when I bought it from Retro Modding for some reason. I wasn't sure why, and I will do what you said and combine the two partitions into one. That seems to make much more sense to me. Not sure why they had it like that, but it was obviously intentional. Perhaps they wanted to store RetroPie on one partition, and the games on another? Again, not sure why.

Don't change the partitions. The RetroPie operating system typically uses 2 partitions. One of them is a FAT32 format, and it will show up on your computer as 'boot' as you noticed. This one is fairly small, and it is not useful for storing things (like ROM files). It's only purpose is to allow the system to boot and use the other partition.

The other partition (that your Windows/Mac computer likely can't see) is the actual operating system and all the data files. Use the "USB Stick" or "SFTP" methods detailed here (https://github.com/RetroPie/RetroPie-Set...rring-Roms) to add games. If you really want to use the "Samba-Shares" method, you would need to install SAMBA first. We remove it for speed reasons.

Do you know what to do to make the L2, R2 and Hotkey buttons work on the gameboy? They are installed correctly and they worked the first time I tried them, but after re-imaging the SD card, they aren't detected by the Freeplay. I found this page on the Freeplay website, but I'm not sure what I need to change to make the buttons work. Again, thanks!

RetroModding likely set these up for you. The mk_arcade_joystick_rpi button driver (https://github.com/TheFlav/mk_arcade_joystick_rpi) needs these to be defined at bootup in the /etc/modprobe.d/mk_arcade_joystick.conf file. If you edit that file (sudo nano /etc/modprobe.d/mk_arcade_joystick.conf), you would probably need to change the gpio parameter to something like
gpio=4,17,6,5,19,26,16,24,23,18,15,14,-20,42,43,-1,41,-1,-1,-1,-1
You may want to ask RetroModding how they had it set up for you.

If you have a fan installed, you may also need to re-install that software.