The Western Digital TV Live is a media player running a Sigma Designs SMP8655 (Non Macrovision version of the SMP8654).

It sports three processors combined into the SoC, a 500MHz MIPS 24KF main CPU+FPU, a 333MHz MIPS 4KEc IPU (Image Processing Unit) and a 333MHz Security CPU supporting conditional access (CA) and digital rights management (DRM).

~ # cat /proc/cpuinfo
system type             : Sigma Designs TangoX
processor               : 0
cpu model               : MIPS 24K V7.12  FPU V0.0
Initial BogoMIPS        : 332.59
wait instruction        : yes
microsecond timers      : yes
tlb_entries             : 32
extra interrupt vector  : yes
hardware watchpoint     : yes
ASEs implemented        : mips16
shadow register sets    : 1
VCED exceptions         : not available
VCEI exceptions         : not available

System bus frequency    : 333000000 Hz
CPU frequency           : 499500000 Hz
DSP frequency           : 333000000 Hz

FLASH Memory

The board contains a single Micron MT29F2G08AAD NAND FLASH with a capacity of 2Gbits x 8 (256MBytes).

/proc # cat sigminfo
dev:    size     offset   name    CS
sigmblk0: 0ff80000 00000000 "CS0-Device" 0
sigmblk1: 00080000 00000000 "CS0-Part1" 0
sigmblk2: 00040000 00080000 "CS0-Part2" 0
sigmblk3: 00300000 000c0000 "CS0-Part3" 0
sigmblk4: 00300000 003c0000 "CS0-Part4" 0
sigmblk5: 01000000 006c0000 "CS0-Part5" 0
sigmblk6: 00800000 016c0000 "CS0-Part6" 0
sigmblk7: 05a00000 01ec0000 "CS0-Part7" 0
sigmblk8: 05a00000 078c0000 "CS0-Part8" 0
sigmblk9: 00020000 0d2c0000 "CS0-Part9" 0
sigmblk10: 00020000 0d2e0000 "CS0-Part10" 0
sigmblk11: 00020000 0d300000 "CS0-Part11" 0

/dev # ls -l /dev/mtd*
brw-r--r--    1 root     root     254,   0 Jan  1  2000 /dev/mtdblock0
brw-r--r--    1 root     root     254,   3 Jan  1  2000 /dev/mtdblock2
brw-r--r--    1 root     root     254,   6 Jan  1  2000 /dev/mtdblock3
lrwxrwxrwx    1 root     root           15 Jan  1  2000 /dev/mtdblock_bootloader -> /dev/sigmblocka
lrwxrwxrwx    1 root     root           15 Jan  1  2000 /dev/mtdblock_kernel -> /dev/sigmblockd
lrwxrwxrwx    1 root     root           15 Jan  1  2000 /dev/mtdblock_romfs -> /dev/sigmblockh

ls -l /dev/sigmblock*
brw-rw----    1 root     root     254,   0 Jan  1  2000 /dev/sigmblocka
brw-rw----    1 root     root     254,   1 Jan  1  2000 /dev/sigmblockb
brw-rw----    1 root     root     254,   2 Jan  1  2000 /dev/sigmblockc
brw-rw----    1 root     root     254,   3 Jan  1  2000 /dev/sigmblockd
brw-rw----    1 root     root     254,   4 Jan  1  2000 /dev/sigmblocke
brw-rw----    1 root     root     254,   5 Jan  1  2000 /dev/sigmblockf
brw-rw----    1 root     root     254,   6 Jan  1  2000 /dev/sigmblockg
brw-rw----    1 root     root     254,   7 Jan  1  2000 /dev/sigmblockh
brw-rw----    1 root     root     254,   8 Jan  1  2000 /dev/sigmblocki
brw-rw----    1 root     root     254,   9 Jan  1  2000 /dev/sigmblockj
brw-rw----    1 root     root     254,  10 Nov 12 12:51 /dev/sigmblockk
brw-rw----    1 root     root     254,  11 Jan  1  2000 /dev/sigmblockl

sigmblocka signblockc YAMON sigmblockd vmlinux_xload.zbf sigmblocke vmlinux_xload.zbf sigmblockh

sigmblockf Splash Screens

RAM Memory

Four 1Gbit Nanya NT5TU64M16DG-AC DDR2-800 SDRAMs have been used for volatile memory providing a total 512Mbytes of RAM.

YAMON PROM Monitor

The board uses MIPS's YAMON PROM Monitor as the bootloader. Source code is available from here.

To break into the YAMON console while booting, press the 0 key.

To initialise the network and obtain an IP address via DHCP:

YAMON> <B>net init</B>
em86xx_eth0 ethernet stop

em86xx_eth0 - full-duplex mode
em86xx_eth0 - 100 Mbit/s
em86xx_eth0 ethernet start
DHCP was successfully configured.
ipaddr:     192.168.0.50
subnetmask: 255.255.255.0
gateway:    192.168.0.254

To load a kernel into memory from TFTP:

YAMON> <B>load -b tftp://192.168.0.251/vmlinux.bin 0x84000000</B>

And then execute:

YAMON> <B>go</B>

Kernel

The YAMON bootloader requires a binary version of the kernel. Use objcopy to generate this file from the vmlinux ELF file.

mipsel-linux-objcopy -O binary vmlinux vmlinux.bin

The default kernel configuration doesn't enable rootnfs. if you try to specify a NFS root, the kernel will display :

VFS: Cannot open root device "nfs" or unknown-block(0,255)<BR>
Please append a correct "root=" boot option; here are the available partitions:

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,255)

To turn this on, enable Networking -> Networking Options -> IP: kernel level autoconfiguration This will then allow you to enable : File Systems -> Network File Systems -> Root file system on NFS

Root FS

The WD Firmware distributes the firmware containing a filesystem image as a .bin file (e.g. wdtvlive.bin)

The filesystem is a CRAM ROM file system. To extract the contents :

tail -c +33 wdtvlive.bin > wdtvlive.stripped.bin
./cramfsck-16k -x dump wdtvlive.stripped.bin