BRM98

Hi, I recently purchased a Harmony Encore cartridge and I can not get it working for the life of me. I put the games on an SD card and then inserted it into the cartridge and whenever I would turn on the 2600 it would just be a black screen. After searching around I found that people who had the same problem got it working again by re-flashing the BIOS so I downloaded the Harmony Software but could not get the cartridge to be recognized by Windows 10 at all. I finally got it recognized on an older Windows 7 machine and was able to re-flash the BIOS. Then when I put the cartridge into the 2600 it would show the spinning logo for a couple of seconds and then just go to a black screen. Turning the 2600 off and on repeats the process one or two more times of spinning logo followed by black screen and then after that when I power it on, it just goes straight to black screen until I re-flash the BIOS again when I can get the spinning logo to show back up a couple more times before just going straight to a black screen. In the FAQ of the manual it says "My Harmony cartridge just displays a spinning logo on the screen, and nothing else happens - what am I doing wrong?" and lists the reason as the SD card not being supported/formatted correctly but the way its worded makes it seem like its referring to the spinning logo constantly being displayed whereas it displays for a second or two for me and then goes to black screen. In any case, I've re-formatted the SD multiple times and tried different SD cards and it's the same thing every time. Also, I'm not sure if this is relevant but I bought the SD version (not the microSD version) and in the manual it says the SD card slot is a push-push design. I'm not sure if that refers specifically to the microSD version but the slot on my cartridge is definitely not a push-push design. Thanks for any help. I'm so excited to take the Harmony cartridge for a spin and it feels so close, yet so far from getting it to work lol. EDIT: Just to add a bit more info, the console itself is a Light Sixer and all the other games I've tried on it (only a handful) work no problem.