PAC PAC-UP USB Updater. The PAC-UP allows you to update the PP-SWI, iAMP-GM1 and soon will allow you to update the firmware on many different PAC interfaces. Allows you to update the firmware on many different PAC interfaces.
The software is pretty easy to use, although the PAC instructions reflect a different version and are at times unclear. However you'll still easily bumble through it. Connect, check versions. Download if needed. Reflash.
In my case, I found out I already had the current firmware at this point. The instruction to first get an updater and reflash the interface with the most current firmware was a trick. But, when I soldered up the harness, plugged everything in,turned it on, all of my dash displays and wheel controls and everything in the Bose system still worked, I was pleased enough with PAC in general. Thanks to ebay, I got the updater and my interface for the retail cost of the interface, so that's still a win.
TL;DR
Great if you need it. Check firmware versions on the interface and website first. You might not need it.
My pac device was already up to date... The fact you have to have this device to update your pac device is ridiculous all on its own. Unless you install alot of stereo equipment you probably won't need this.