collector {dt.:Sammler}

collected: unbrick dockstar with buspirate

By killing the nand off his dockstar a colleague gives me the final trigger to buy a BusPirate – an awesome tool for dealing with several buses and protocols – including JTAG. I found tree great HowTo’s on debricking the dockstar here, here and here.

Unfortunately there are some stumbling blocks on the way to a recovered dockstar…

1. dockstar uses 3.3V-level for the serial communication – so a ftdi232-based serial-ubs-adapter could do the job. But my colleague decides to use some china crap (see image below) with an PL2303 – normally no problem. But two weeks ago I updated my M$-PC to Windows7/64. The driver offered by Prolific (version 1.0.0.0) won’t work anymore for this „brand new OS“. Someone mentioned a a GPS-device that is based on/contains the PL2303. The driver for that GPS contains the driver for the PL2303 with version = 1.2.1.0 and… it works for Win7/64.

2. BusPirate is advertised with the attribute „also a JTAG-device by using in conjunction with OpenOCD“. But this depends on the version of the firmware of the BusPirate. My unit was delivered with FW 5.10 – won’t work with OpenOCD (I did a fresh build with the GIT-sources and a manual fetched 0.5.0 – booth won’t work). I’d go down step-by-step in FW version till FW5.8 (okay, 2 steps != a long way) and now it works. Sadly I had to disconnect/connect the BusPirate before I could start a new OpenOCD session every time.

below the procedure that works for me…
in the openocd-shell:

> init
> halt [[[press reset&hold@dockstar, press return]]]
Halt timed out, wake up GDB.
[[[release reset@dockstar]]]
target state: halted
target halted in ARM state due to debug-request, current mode: Supervisor
cpsr: 0x000000d3 pc: 0xffff0000
MMU: disabled, D-Cache: disabled, I-Cache: disabled
> dockstar_init
> load_image uboot.kwb 0x800000
524288 bytes written at address 0x00800000
downloaded 524288 bytes in 100.608101s (5.089 KiB/s)
> resume 0x800200              
> 

now move (fast) to the serial terminal, press <any> key…

U-Boot 2010.09 (Oct 23 2010 - 11:49:22)
Marvell-Dockstar/Pogoplug by Jeff Doozan

SoC:   Kirkwood 88F6281_A0
DRAM:  128 MiB
NAND:  256 MiB
*** Warning - bad CRC or NAND, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   egiga0
88E1116 Initialized on egiga0
Hit any key to stop autoboot:  0
Marvell>> nand erase

NAND erase: device 0 whole chip
Skipping bad block at  0x06ba0000
Erasing at 0xffe0000 -- 100% complete.
OK
Marvell>> nand write.e 0x800000 0x0 0x80000

NAND write: device 0 offset 0x0, size 0x80000
 524288 bytes written: OK
Marvell>>reset

remarks: nand erase cleans the complete nand (ffe0000 = 256 MiB),
the write.e is used for skipping bad blocks of the nand. since there is no dockstar-system in the nand the dockstar reboots and reboots and reboots…

Result: DockStar is back to live, and I got a BusPirate.