Arch Linux (64 bit) - Unable to determine board revision

[Hoekstraa]

I run Arch Linux 64-bit on a Raspberry Pi 3B.
When I run either 'gpio -v' or 'system-gpio' I get the following error:

Oops: Unable to determine board revision from /proc/cpuinfo
 -> Unable to open /proc/device-tree/system/linux,revision
 ->  You'd best google the error to find out why.

When I run /proc/cpuinfo I get

processor       : 0
BogoMIPS        : 38.40
Features        : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 4

..(times 4, incrementing 'processor')

I'm guessing this is not enough info considering there are multiple Pi's with this processor. So continuing with the files unable to be opened, these files do not exist by default in the 64-bit install described here: Arch Linux Arm.

But there is a file called /proc/device-tree/model which contains the following:

Raspberry Pi 3 Model B

Is it possible that we can make a case for checking this file for the model too?

[tirithen]

I'm still having the same issue with a Raspberry Pi 3 Model B, same /proc/cpuinfo info, was anyone able to solve this?