ubuntu@ubuntu-VirtualBox:~/Desktop/rockbox/utils/nwztools/upgtools$ ./upgtool -e -m nwz-a86x -o nw_wm_fw NW_WM_FW.UPG
Preliminary
  MD5: d77b8c8d0eed2509741734fc069180c0 Ok
Keys
  KAS: ddb2f33e1545316a783f307c1ba538c5
  Key: c824e4e2
  Sig: 7c262bb0
Header
  Signature: 7c262bb0 OK
  Files: 3
  Pad: 0x0
Files
  File 0
    Offset: 0x38
    Size: 0x722
  File 1
    Offset: 0x760
    Size: 0x327600
  File 2
    Offset: 0x327d60
    Size: 0x2f4bbb7