To get it working on my board (which has just 64kb memory) I had to make a little tweaks event though it looks the same.
Due to lower memory (64kb vs 128kbI received error “Last page at 0x08010913 is not writeable”) I had to checkout older and smaller version of blackmagic.
git clone firstname.lastname@example.org:blacksphere/blackmagic.git
I checked out older revision of blackmagic
git checkout 1b2cd547bc79c0693a0c64232211e884b1348348
Then after the build, flashing went smoothly.
On windows I had to install drivers(with driver signature enforcement off).
Hope it works for you!