Since CFast cards are still expensive, people are still looking for more affordable ways to record on BlackMagic URSA and URSA Mini camera. Here is a hack (although the manufacturer calls it a “solution”) for fooling the camera that it is recording to CFast cards, but actually recording to SSDs.
You can get the Atoch C2S CFast to SSD Solution for BlackMagic URSA cameras on BH Photo Video, Adorama, eBay, Amazon
Last year, Tom shared a DIY solution, or adapter, that does the same thing as the Atoch C2S. You can read more about it here.
You mention that a prt for the DIY hack is not available anymore. Which part?