Homebrew My CFW o3DS won't play my DS games?

[heliopause]

I felt the urge to play some Pokemon Heartgold and put it in my CFW 3ds, I opened it up and just got a black screen that played my 3DS themes song. No buttons worked and I had to hard reset it. I panicked and quickly put in my Pokemon Y, which worked fine. I used my Omega Ruby and Super Smash Bros just fine as well. I wondered if my Heartgold got damaged somehow and tried to run my Platinum, I got the same black screen with theme music playing. I tried both my White games and a Professor Layton game just to be sure.
I popped out my SD card and got the same results.
Does anyone have any idea why it's not reading my DS cards? They are all legit and have worked before I got CFW. My 3DS cards run fine, just my DS ones.
I have an old DS lite but still, it's nice to play it on my 3DS.

 

[hurricane_matt]

https://3ds.guide/troubleshooting

 

[heliopause]

Thanks haha, my google search initially didn't give me that somehow, just old message board threads.