Yeah -- that's probably a good point. Don't run the vendor kernel. That's honestly a good rule for most ARM boards -- you should avoid the vendor provided kernel tree.

To clean up the odd PCIe behavior on the Espressobin with mainline 4.17, there are 6 kernel patches required. Arch and OpenWRT both already ship them, and I'm in the process of getting them in to Buildroot. I'd expect they'll land in the mainline eventually.

https://github.com/jrb/buildroot/tree/espressobin/board/glob...

edit: sorry; 3 PCI patches. The other 3 mitigate other board/chip oddities.