[3DS] bottom_menu.png not working, and another weird bug

First and foremost consider this:

• Only RetroArch bugs should be filed here. Not core bugs or game bugs
• This is not a forum or a help section, this is strictly developer oriented

Description

the new 1.9.9 update on 3ds does not seem to be working properly for the bottom_menu.png file. i have it in retroarch/assets/ctr, but when I start a game all the bottom screen says is "bottom_menu.png not found in the assets/ctr folder"

i once accidentally got it working, but it messed up launching retroarch and set a old pcsx core (1.7.5) as retroarches default core (where it normally installs dosbox on first launch and stuff). so every time I opened retroarch it would crash and say something like 1.7.5 pcsx core not found, cant install, or something.

Expected behavior

what I expect to happen is the dumb thing would just use the bottom_menu.png as it should

Actual behavior

what I said above

Steps to reproduce the bug

1. [First step]
2. [Second step]
3. [and so on...]

steps to reproduce it, I have no idea. i just turn the pcsx core on and launch a game, and it doesn't work

Bisect Results

[Try to bisect and tell us when this started happening] it always happened

Version/Commit

You can find this information under Information/System Information

• RetroArch: [version/commit] build date says 9/5/2021, I downloaded the most recent version from here https://buildbot.libretro.com/stable/1.9.9/nintendo/3ds/

Environment information

• OS: [The operating system you're running] 3DS OS (v11.15)
• Compiler: [In case you are running local builds] GCC (10.2.0) 32-bit

Start by reproducing the issue on RetroArch 1.9.9 for Nintendo 3DS with bottom_menu.png in retroarch/assets/ctr and the PCSX core enabled. Inspect the 3DS asset lookup and startup/core-selection paths mentioned by the symptoms. Done means the bottom screen loads bottom_menu.png and RetroArch starts without selecting or requiring the old PCSX core.