Two years ago I made a rather simple circuit board to be able to program Atmel ATtiny microcontrollers with an Arduino board as ISP. I shared my excessive PCBs and made the design open source. The design has proven to be pretty successful, and I was asked multiple times to make a more flexible follow-up version. So I recently started to design the revision 2.0 which should combine ISP and HVSP/HVPP features.
This is a preview (i.e. the design is still buggy) but the final goal is to support the default “Arduino as ISP” option as well as HVSP/HVPP programming modes. The new feature can be useful to recover ATtiny (and ATMega) controllers with incorrect (broken) fusebits settings.