that's right, I have to figure out whether the interface card I bought is the problem here, or the linux kernel drivers for it, causing instant [kernel crash? soft-reboot trigger? cpu bug slam??] when attempting to use the bus it provides. Except, we're talking about firewire here, so there's nobody to go ask anymore, and I have to do something far funnier than usual: I am going to download a ubuntu studio livedvd image from 2015~2020 and see if it works there. I am debugging hardware by dumpster-diving live OS images, I always knew some people need to do this but I never expected I'd become the trash woman.
rejoice! tis a hardware issue, meaning i can throw another $15 at it and fix it instead of needing to spend a few months finding the latest kernel version firewire works on