They’ve added installed support for the atmega328p in avrdude.conf - That’s good.
The changelog indicates that they have tried to make the code more robust in its dealings with the USBtinyISP. That’s good.
But it still doesn’t work properly. I can’t get a good burn.
With my code size getting bigger now (all of 700 bytes) my chances of a good burn and verify have fallen to around 0.
Given that you can slow down the SPI side of USBtinyISP to a slow crawl by using the -B parameter, and it still fails, I tend to blame the soft USB implementation for my woes.
I added zener diodes to clamp the USB data lines. These were present on the USBTinyISP design but had been left out on the AVR programmer. Hacking the board was too fiddly, so I cut the cable and added them there instead.
Before: Board not seen by USB host controller when plugged directly into PC.