Starting to fix a Dockstar

I picked up a pair of Dockstars, little low-powered ARM-based devices, and managed to brick them both. One has a broken OS install, the other has a full-on dead bootloader.

My original plan was to place one Dockstar just inside the DSL gizmo (no longer just a modem, alas) to use for DNS, authentication, VPN endpoints, waking ethernet devices, etc. The second’s to become a read-mostly photo and music server and backup host. Right now they’re just taking up space.

One bricked Dockstar just needs a serial console. Not RS-232 but rather a direct 3.3v, three-line UART. The second will need a full JTAG adapter. I actually bricked them a few months ago, but I haven’t had time to consider them until lately. Along comes Sparkfun Electronics’s “Free Day,” and I manage to reach their server just often enough to cover their Bus Pirate clone, a nifty gizmo that has such a UART, supports reconfigurable JTAG, and many other things over a USB connection.

This seems perfect considering the only other affordable JTAG dongles seem to require a parallel port. None of my machines have one. (Progress? sigh.)

Initial pass? Not so good. Something strage was happening just talking to the Bus Pirate. Too many characters were being dropped… but only over one particular USB port on my laptop. Great. Found a possibly busted USB port.

I’m rather out of practice with low-level serial goo, so it took a few hours to upgrade the Bus Pirate’s bootloader and firmware. I also was working with a jury-rigged jumper situation. The Sparkfun clone lacks the easy jumper pins. So I went with the classic paperclip and tape solution. That did make flashing the bootloader a bit worrisome, but now I no longer need the jumper.

Now I’m facing dropped and mangled characters coming from the Dockstar. I’m not entirely sure which Dockstar I played with today, so that might be a symptom of a corrupted u-boot on the Dockstar’s side, or it might be a problem with the Linux USB tty driver in my rc kernel. But there’s a similar report in the Bus Pirate support web goo thingy that looks unresolved. We’ll see.

It’d be nice to turn off my desktop when I’m not home while still being able to start it when I need it.

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