I stumbled across this issue attempting a Gentoo install using their
2004.3 distribution and the 2.6.x Kernel. They changed the name of the
memory kernel parms from mem to memmap.
With 2.4.x and older kernels you used a line like this to boot the
kernel on a mchine with 512 meg of ram
kernel mem=exactmap mem=640K@0 mem=511M@1M
With the 2.6 kernel that line now reads
kernel memmap=exactmap memmap=640k@0 memmap=511M@1M
To boot the Gentoo minimal install CD:
gentoo-nofb memmap=exactmap memmap=640k@0 memmap=511M@1M
Good Luck!