Has anyone had any luck using the DVRFlash 2.2 utility to flash their Pioneer DVD-RW's firmware?

I'm trying to go from firmware revision 1.10 to Pioneer's official 1.22 release using DVRFlash 2.2. It seems that DVRFlash recognizes my drive, and recognizes the firmware file I'm using, but will not proceed to the actual flashing part.

It hangs here:
Code:
Commandline:
  dvrflash PIONEER R7100107.122


Drive Information:
   Description : PIONEER DVD-RW  DVR-107D
  Firmware Rev : 1.10
 Firmware Date : 04/02/12
  Manufacturer : PIONEER  
Drive is in normal mode.
...and won't go any further, even after letting it sit for an hour. Apparently, the next line that should appear should be, "Are you sure you want to flash this drive? (y/n)" but that prompt never appears for me -- it just hangs on the above text.

I've tried using both the verbose (-v) and force flash (-f) flags, as well as using them both together -- same results (hanging) every time.

My question is this -- has anyone else successfully used DVRFlash to flash their Pioneer drive, and if so, did they encounter this problem, and how did they get around it?

My last resort is to remove the drive from my Mac, install in a PC, and use Pioneer's own firmware flasher to get the job done. Last resort, though, as I'd like to find out why DVRFlash is hanging...