after a fis init:
RedBoot> fis list
Name              FLASH addr  Mem addr    Length      Entry point
RedBoot           0xA8000000  0xA8000000  0x00030000  0x00000000
FIS directory     0xA87E0000  0xA87E0000  0x0000F000  0x00000000
RedBoot config    0xA87EF000  0xA87EF000  0x00001000  0x00000000
RedBoot>
RedBoot>
RedBoot>
RedBoot> load -r -b %{FREEMEMLO} openwrt-atheros-2.6-root.squashfs -m ymodem
CCRaw file loaded 0x80040800-0x802c07ff, assumed entry at 0x80040800
xyzModem - CRC mode, 2(SOH)/2560(STX)/0(CAN) packets, 4 retries

RedBoot> fis create -f 0xA8030000 -l 0x00700000 -e 0x00000000 rootfs
... Erase from 0xa8030000-0xa8730000: ..........................................
......................................................................
... Program from 0x80040800-0x802c0800 at 0xa8030000: ..........................
..............
... Erase from 0xa87e0000-0xa87f0000: .
... Program from 0x80ff0000-0x81000000 at 0xa87e0000: .

RedBoot> fis list
Name              FLASH addr  Mem addr    Length      Entry point
RedBoot           0xA8000000  0xA8000000  0x00030000  0x00000000
rootfs            0xA8030000  0xA8030000  0x00700000  0x00000000
FIS directory     0xA87E0000  0xA87E0000  0x0000F000  0x00000000
RedBoot config    0xA87EF000  0xA87EF000  0x00001000  0x00000000

RedBoot> load -r -b %{FREEMEMLO} openwrt-atheros-2.6-vmlinux.lzma -m ymodem
CCRaw file loaded 0x80040800-0x801007ff, assumed entry at 0x80040800
xyzModem - CRC mode, 2(SOH)/768(STX)/0(CAN) packets, 4 retries

RedBoot> fis create -r 0x80041000 -e 0x80041000 vmlinux.bin.l7
Can't locate c0000(786432) bytes free in FLASH

RedBoot> fis list
Name              FLASH addr  Mem addr    Length      Entry point
RedBoot           0xA8000000  0xA8000000  0x00030000  0x00000000
rootfs            0xA8030000  0xA8030000  0x00700000  0x00000000
FIS directory     0xA87E0000  0xA87E0000  0x0000F000  0x00000000
RedBoot config    0xA87EF000  0xA87EF000  0x00001000  0x00000000
RedBoot>