I bought 40 attiny13a chips from china but after receiving them, I couldn't program them with my USBasp programmer. I tried all of them with the same result - chips did not respond to the programmer. I quickly constructed Arduino based high voltage programmer using bunch of resistors and a transistor based on this link so I could read the fuses. They are not set to default values - RSTDISL and both BOD bits are set, so the high fuse is 0xF8.
Problem is, I can't change those fuses with the same programmer even though it can read chip signature correctly and fuses values also seams sane. When trying to change fuses nothing happens, microcontroller seems to be ignoring the commands.
Exactly the same setup works for my older chips (I can change fuses without problems), though, so I think my DIY programmer does work. The seller claims that the chips are ok and my circuit has to be faulty. Am I missing something here or all 40 chips are broken in this strange way?