ARM support for NixOS is a work-in-progress, but is progressing quickly.

The support varies depending on the architecture and the specific boards. The way the ARM integration is built into NixOS is by making generic builds the first-class citizens; as soon as there is upstream support for the board in the kernel and the bootloader, NixOS should work once updated to these versions. It is still possible, when needed, to build and use a customised bootloader and kernel for specific boards[reference needed]. At this moment in time (early 2018) only AArch64 is planned for full support upstream. Though, neither armv6l or armv7l are being ignored, fixes are worked on and approved as needed; what's missing is support and upstream builds being maintained in binary form.