The Freedombone system currently supports only a few ARM single board computers. The supported list can be found in the manpage of the freedombone-image command, but basically it's the same as for FreedomBox but without the Raspberry Pi.
Freedombone doesn't support systems which need a proprietary bootloader blob, but if you have an ARM board which does need one of those then so long as you can somehow get Debian 9 onto it then you can still install the system.
I've recently added support for 64bit ARM architecture (aarch64), since many of the newer boards now use this, and also some instructions on how to install Freedombone on an Armbian operating system. Armbian supports a large number of boards and so this means that any you choose could become a home server.