I recently attempted to install debian from a jessie image, each the
netinstall release of alpha 1, as well as a weekly image.  Each
attempt failed during partitioning.  It did detect my currently
installed arch linux setup (details below), but while trying to apply
my requests, it got stuck at:

"Creating EFI-fat16 fil system in partition #1 of SCSI1 (0,0,0) (sda)..."

The system currently has GPT partitions for /, /home, swap, and /boot;
I was trying to format all partition except for /home .  The installer
recognized /boot as the ESP successfully, but failed to continue.
Googling suggests a couple of others with issues [1], with the only
solution really to manually do the installation of the contents to the
partition after the fact.

[1] http://forums.debian.net/viewtopic.php?f=17&t=113912