I did this to flash:
RedBoot> baudrate -b 115200
RedBoot> fis init
RedBoot> load -r -b %{FREEMEMLO} openwrt-atheros-2.6-root.jffs2-64k -m ymodem
RedBoot> fis create -f 0xA8030000 -l 0x00700000 -e 0x00000000 rootfs
RedBoot> load -r -b %{FREEMEMLO} openwrt-atheros-2.6-vmlinux.lzma -m ymodem
RedBoot> fis create -r 0x80041000 -e 0x80041000 vmlinux.bin.l7
RedBoot> reset

And this is what happens:
== Executing boot script in 10.000 seconds - enter ^C to abort
RedBoot> fis load -l vmlinux.bin.l7
Image loaded from 0x80041000-0x80289086
RedBoot> exec
Now booting linux kernel:
 Base address 0x80030000 Entry 0x80041000
 Cmdline :