We just uploaded Bus Pirate firmware v2.1 release candidate 2 for all hardware versions, including the first release for Bus Pirate v3.

Since v2.1-RC1, we’ve combined the hardware and software I2C libraries. This applies the RC1 ACK/NACK management system to the hardware library without duplicating a bunch of code. Some have reported success using the updated hardware I2C library on revision 3 hardware. We’ll post a complete overview of the new I2C library in a few days.