While devising ways to get a stable and reliable timer source for my ATtiny2313 and realizing that I could recycle the /RESET pin as a regular I/O pin in order to have T1 (PD5) free, I absentmindedly flashed the fuses to activate RSTDISBL. Let's just say that now I know that that wire from the ISP connector isn't there just because it looks cute. ;)
So fellow newbies beware: RSTDISBL is potentially destructive, and you need to go for the high voltage programming. In my case I'm just pretending I lost a few coins off my wallet, as I have no such programmer nor I have the desire to build myself one (it looks quite complicated, from what I've seen).