I gave up on Amithlon a few years ago. It is very unfortunate that Gary 'DrBombcrater' Colville has decided to violate the GPL by not releasing the source code he used to build the newer kernels, hence making it virtually impossible to compile kernels with support for newer chipsets and drivers. I never got gfx board support running except for the 8-bit VESA framebuffer, never got the Ethernet NIC working and only got sound support by heavily patching some binaries with newer PCI-IDs. It was a mess.
With the advance of WinUAE, I hardly see any use for Amithlon any longer.