Un-Bricking Linux Plug Computers

An anonymous reader writes "Accidentally 'bricking' a little Linux plug computer doesn't have to be forever. This is a good howto on repairing a non-booting Linux plug computer. For example if it uses the uBoot environment then it already has some good built-in recovery tools. The article also mentions ESIA, the Sheevaplug installer, openocd, and GuruPlug."

Comments

Oblig. pedantry

[butalearner]

Isn't the fact that you can "unbrick" it mean it's not really bricked?

Also I think this requires JTAG, which comes with Sheevaplug but is sold separately from Guruplug, and AFAIK is not available on the PogoPlug, et al. So, not quite so useful for me (I just picked up a PogoPlug on the cheap with the intent of running Plugbox Linux.

Re:Oblig. pedantry

[fuzzyfuzzyfungus]

In principle, you are correct. In practice, an increasing number of devices(especially space or cost constrained ones) implement "RS-232" that behaves pretty much exactly the same way as would be expected by anything post-20mA loop, with the exception of voltage. For cost and board space reasons(and because they are not intending to address the "terminal across the electrically noisy building from the minicomputer" use case), they omit any voltage conversion or protection circuitry and simply depend on the attached hardware to do either 5v/0v or 3.3v/0v, or whatever their logic-level happens to be.

Even an increasing number of supposedly-genuine RS-232 devices(especially laptops) don't generate anything near the +-12 swing of the old days. 12v/0v is more likely, or even 5v/0v, though such devices tend to, at least, have better tolerance for over-voltage than the little guys do.

Because it is so close to RS-232(all you need is a dumb level converter, no logic/protocol translation required), I tend to fall into calling it "RS-232" colloquially, even though it technically isn't.

Agree: it's NOT "bricked"

[KWTm]

Isn't the fact that you can "unbrick" it mean it's not really bricked?

Hear hear! Let's recall that "brick" basically means "turning your equipment into something completely worthless, equivalent to a brick".

I propose the following "USB cable" test:

Has your device been rendered so unusable that you'd be willing to give it to me if I gave you a USB cable?

If the answer is "yes", then you have bricked your device. Congratulations.

If the answer is "no, let me work on this for a bit --I think I can restore partial functionality by pressing this reset button for 30 seconds, and then at least it will function as a glorified wall clock", then this is not "bricked".

If you say, "This is the third time I've bricked my device --I had to SSH into it and do 'sudo reboot'" --then the brick is in your brain.

Now, having said this, it's possible that the owner of the computer didn't know it was possible to undo the damage, in which case, yes, the device is bricked because he might as well have traded it in for a USB cable, prior to knowing how to salvage his device.

You can substitute any marginally useful but cheap piece of equipment for "USB cable".

Disclaimer: no, I haven't RTFA.