Neither device has a CPU that supports the x64 instruction set. These both have arm chips, though they are both capable of 64 bit operation.

It's not quite what you're asking for (and I'm asking for it too) but I have an Asus RT-AC56U running dd-wrt. It is an arm box with a decent amount of RAM, all gig ports and supports 802.11ac. It doesn't quite run Debian, but I have the next best thing: an SSD attached via USB3 with a Debian install that I run services out of via chroot from a boot script - I essentially turned off all of dd-wrt's services other than the wireless access point and then use the dd-wrt's kernel with a Debian userland for everything else. It took some messing around to get it all working, but it just works now and allowed me to shut off a much bigger device.