RedBoot> 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> load -r -v -b %{FREEMEMLO} openwrt-atheros-2.6-vmlinux.lzma
... 

# you do not have to provide the flash address as we are writing after the boot block

RedBoot> fis create -r 0x80041000 -e 0x80041000 vmlinux.bin.l7
...
RedBoot> fis list
Name              FLASH addr  Mem addr    Length      Entry point
RedBoot           0xA8000000  0xA8000000  0x00030000  0x00000000
vmlinux.bin.l7    0xA8030000  0x80041000  0x000C0000  0x80041000
FIS directory     0xA87E0000  0xA87E0000  0x0000F000  0x00000000
RedBoot config    0xA87EF000  0xA87EF000  0x00001000  0x00000000
... 

# the calculation of the free space:
# "FIS directory FLASH addr" - "vmlinux.bin.l7 FLASH addr" + "vmlinux.bin.l7 Length"
# 0xA87E0000 - 0xA8030000 + 0x000C0000 = 0x006F0000
# The size of the rootfs space 7274496 bytes

RedBoot> load -r -v -b %{FREEMEMLO} openwrt-atheros-2.6-root.jffs2-64k (or any other rootfs image)
RedBoot> fis create -l 0x006F0000 rootfs

RedBoot> fis list
Name              FLASH addr  Mem addr    Length      Entry point
RedBoot           0xA8000000  0xA8000000  0x00030000  0x00000000
vmlinux.bin.l7    0xA8030000  0xA8030000  0x000C0000  0xA8030000
rootfs            0xA80F0000  0x80040800  0x00460000  0x80040800
FIS directory     0xA87E0000  0xA87E0000  0x0000F000  0x00000000
RedBoot config    0xA87EF000  0xA87EF000  0x00001000  0x00000000