In a recent commit, the call to lb binary_hdd was accidentally removed. Also, it seems that using ext4 doesn't work in live-build right now (the allocated image size is too small), so we'll switch back to fat16 for now. Note that this does not completely fix disk builds, there seems to be a problem with the bootloader still.
The "progress" mode was renamed to "progress-linux" in live-build 3.0~a67. Since we use an existing chroot, with preinstalled packages and a configured sources.list, this didn't actually break regular builds. However, it did break building hdd images, since the default disk label is based on the mode, but lb_binary_hdd can't handle an empty disk label.
This allows these options to be used during the upgrade process as well as during the build process. Additionally, this allows these boot options to be specific to a version of the chroot, since they can be changed when upgrading. This needs a companion change in the chroot repository to work.
These images can be writting to a hard disk or USB stick, using a read-write FAT filesystem which allows editing the live.cfg file.