Thanks so much Cyan, that was it. I was on HBC 1.0.8, but it was IOS61. I installed IOS58, reinstalled HBC and all is good now.
It didn't fix the priiloader problem unfortunately, but I haven't played with that much yet.
I'm having an issue with the latest USB Loader GX release. I hadn't upgraded in probably a year, and everything was going fine with what I had (that'll teach me to upgrade!) So I just upgraded to the latest v2.2 (r1100). It works fine when I run it from HBC, but when I try it from the...