apu2: 105 € (+), no SFP (-), DB9 serial (+), GOARCH=amd64 (+)
Basically, the apu2 costs half (I now have 3), has a real serial port (now permanently attached to my workstation) and an architecture (amd64) which is closer to what gokrazy already supports (arm64) and more likely to be useful to others — I could find way more suitable (≥ 2 ethernet ports) amd64 boards/mini-PCs than 32-bit arm boards.
The apu2 has all the Omnia has (aside from the built-in SFP), and is well-supported by PC Engines and their vendors. They run coreboot and even sell you recovery SPI flash chips for a few bucks if you want to change coreboot yourself :).
The HAL is Linux in this case, but you might need to send pull requests to enable additional drivers, depending on the hardware.
The currently supported platforms are the Raspberry Pi 3 B, Raspberry Pi 3 B+, the PC Engines apu2c4, and qemu x86-64 (I’ll update gokrazy.org with an overview about this in a minute). As long as your hardware is similar enough to one of these, chances are things just work.
I guess that has to do with firmware and schematics not always being available. Current consumer routers often have no or little documentation on the internal workings and some have started to limit functionality if you can't use vendor-signed firmware. On the other hand, as soon as you can run stock linux kernels with reasonable performance, gokrazy becomes possible again.
Edit: I was wrong, the Turris has docs and firmware to play with.
