replaced fbalpha_libretro.elf with fbalpha_libretro.rpx and instead of giving me the error it straight up froze the consolethe rpx (and 2.1) is the channel version. You need the 1.4 release. https://github.com/dimok789/homebrew_launcher/releases/download/1.4/homebrew_launcher.v1.4.zip
(You may also need to update payloads.)
As for the rpx part, I meant the rpx zip in the retroarch nightlies.