Tag Archives: brick

Unbricked my old SheevaPlug

Few months ago one of my friends borrowed SheevaPlug from me. About two weeks later he gave it back — bricked… I did not had time to play with it so it landed on shelf.

Yesterday I took it and decided to get it back to live. Requirements:

  • bricked SheevaPlug (v1.0 without SATA)
  • power cable
  • mini usb cable
  • usb thumb drive
  • OpenOCD (“apt-get install openocd”)
  • cross compiler (“apt-get install gcc-arm-linux-gnueabi” under Ubuntu)
  • U-Boot sources (HEAD of mainline)
  • Linux sources (also HEAD of mainline)
  • serial terminal (picocom, minicom, screen etc)
  • few terminals or terminal multiplexer (I used tmux)


  • Connected power and mini usb cables to SheevaPlug. Desktop recognized usb-serial device as /dev/ttyUSB1.
  • Connected to it with serial terminal. Nothing appeared there of course ;)
  • Run OpenOCD: “cd /tmp/;sudo openocd -f /usr/share/openocd/scripts/board/sheevaplug.cfg -s /usr/share/openocd/scripts”. SheevaPlug was detected.
  • Connected to OpenOCD: “telnet localhost 4444″.
  • Built U-boot:
export CROSS_COMPILE=arm-linux-gnueabi-
make mrproper
make sheevaplug_config
make u-boot.kwb
  • Copied “u-boot” to “/tmp/uboot.elf” and used “reset;sheevaplug_init;load_image u-boot.elf;resume 0x00600000″ — landed in U-Boot ;)
  • There is “sheevaplug_reflash_uboot” macro but it was not working for me. So I used U-Boot to flash itself:
Marvell>> usb start
Marvell>> fatload usb 0:1 0x0800000 u-boot.kwb
Marvell>> nand erase 0x0 0xa0000
Marvell>> nand write 0x0800000 0x0 0xa0000
Marvell>> reset
export CROSS_COMPILE=arm-linux-gnueabi-
make mrproper
make kirkwood_config
make menuconfig (set INITRAMFS_SOURCE to /dev/initfs)
make uImage
  • Copied “arch/arm/boot/uImage” to USB thumb drive and inserted it into SheevaPlug.
  • Booted image:
Marvell>> set ethaddr 'c0:ff:ee:c0:ff:ee'
Marvell>> set bootargs 'console /dev/ttyS0,115200 rw'
Marvell>> usb start;fatload usb 0:1 0x800000 /uImage;bootm 0x800000
  • Landed in nice and small Ångström distribution image ;)
  • Went to Ångström online image builder and built console image (task-base based).
  • Built Linux kernel (this time without initramfs):
export CROSS_COMPILE=arm-linux-gnueabi-
make menuconfig (unset INITRAMFS_SOURCE)
make uImage
  • Copied “arch/arm/boot/uImage” to USB thumb drive and inserted it into SheevaPlug.
  • Prepare NAND for UBI:
# mount none /dev -t devtmpfs
# udhcpc eth0
# opkg-cl update
# opkg-cl install mtd-utils
# ubiformat /dev/mtd2
# ubiattach -p /dev/mtd2
# ubimkvol /dev/ubi0 -N rootfs -s 490MiB
# ubiupdatevol /dev/ubi0_0 /media/sda1/angstrom-task-base.ubifs
# mount -t ubifs ubi0:rootfs /media/rootfs
# chown -R root:root /media/rootfs
# cp /media/sda1/uImage /media/rootfs/boot
# sync
# reboot
  • Another reconfiguration in U-Boot:
Marvell>> bootargs 'console=ttyS0,115200 rw ubi.mtd=2 rootfstype=ubifs root=ubi:rootfs'
Marvell>> bootcmd 'ubi part nand0,2; ubifsmount rootfs; ubifsload 0x800000 /boot/uImage;bootm 0x800000'
Marvell>> mtdids 'nand0=orion_nand'
Marvell>> set mtdparts 'mtdparts=orion_nand:512k(uboot),4m@1m(kernel),507m@5m(rootfs)'
Marvell>> save
Marvell>> reset

And now my SheevaPlug is operational again. Boots from NAND with latest U-Boot and Linux. There is around 440MB free still on NAND (not counting 4MB partition where kernel was expected to be). I can put it back on shelf now.

The only parts which I needed to compile were U-Boot and Linux kernel. I could skip bootloader and use binary image from Internet but prefer to know what my machines run (and building U-Boot is really easy). Initramfs support in Linux is real live saver as I did not had to play with initrd etc — just build image and boot it. The only problem was that devtmpfs was not auto mounted (even if option in kernel was selected).

I could also use one of those “easy installers” made by PlugComputer community but I found such solutions more complicated (fetching binaries, finding requirements etc) than the one I used.

Sharp Zaurus JTAG cable

From time to time people are asking about schematics of JTAG cable for Zaurus machines. Such cable can be used to restore flash memory content after destroying it.

For all models newer then collie (SL-5000/5500) there is a hope still as they are much harder to brick. User can enter “Diagnostics menu” via magic keycombo (which usually is holding “D” and “P” during Power key on boot) and then use “NAND Restore” function (NAND Backups are available in few places — TRIsoft is one of them).

Anyway below you should see schematics of such cable — taken from collie service manual. On Zaurus side you have to use Hoshiden TCX3106 connector (docs were available on Sharp Deutschland website) and is available for few USD in Five Star Associates. How to use cable? Do not ask me — I never had to use JTAG.

Sharp Zaurus JTAG cable schematics