It´s very easy to reconstruct the ROM. Talk with @tsialex I have backups and mattecards for two Mac Pros 5,1Sadly my old 2009 4,1->5,1 cMP bootrom finally failed
Seen the nMP 2019 deals but decided to be cheap and keep saving for a Studio Ultra
Was able to snag a trashcan 6,1 cheap locally, swapped over my ssd, and a quick OCLP rerun, back in business
Some weeks ago, it failed my ROM in one of them. I inserted my Matte Card and continued working in seconds.