FEX unable to work - can't set rootFS, trying to rerun the script gives PPA failed to install
I'm trying to get steamCMD running so I can easily manage a server software that's only x86 compatible. After setting up FEX, I am certainly sure that I configured rootFS from the installer. yet I can't run SteamCMD, as it reports 
`Invalid or Unsupported elf file.
This is likely due to a misconfigured x86-64 RootFS
Current RootFS path set to ''
RootFS path doesn't exist. This is required on AArch64 hosts
Use FEXRootFSFetcher to download a RootFS`
Rerunning the installer gives
`PPA failed to install
apt sources failed to update. Not continuing`
PPA Status reports as installed in the download log btw. I'm unsure what to do