So what if it is outdated? Use what works for you.
You people seriously need to get off your high horses and let people use what they want.
This. So much this. While if someone asks me what cfw they should use on a new setup, I certainly wouldn't recommend rxTools at this point, if someone does have a working rxTools setup, and doesn't want/need the features of the newer cfw's, then by all means, leave them alone to use what's working for them. That being said, being that the OP's question is in regards to GBA stuff, it might be a better idea for them to look into a9lh, since it supports GBA and such right out of the box with luma/cake's (because it can survive the reboot properly and boot back into a patched up environment).