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[LavaChild]

From a working (boots and communicates over SSH) GuruPlug (Server Plus), is it possible to reinstall one or more of the following without the need for the JTAG module:

a) U-Boot
b) Kernel
c) RootFS

I have found the 'stock' files for each of these documented on the internet but the instructions use a JTAG module. Can any of the above items be installed without this from a working 'plug? Where possible, can you please give instruction on how to complete this.

Thank you.

[Confusticated]

Yes, but not without risk!
If you have serial console (say via a £5 USB to 3v3 serial adapter, sold for tethering phones) it can be done with u-boot.
At a greater risk, it can be done from within Linux itself using the mtd-utils.
Just because something is possible, is not a good reason to try it.

the instructions use a JTAG module

There is a reason for it, of course you could take the high risk option, and then buy a JTAG when\if it all goes pear-shaped, and hope that you can get the JTAG set up and working without being able to test. You might want to search the forum for the problems people have had setting up the JTAG.

Ask yourself this question 'How much value do you put on having your plug working' ?
If its more than £30, buy a JTAG.

[LavaChild]

Hi Confusticated,

Thanks for your very detailed reply.

I do not put a high value on my plug working and would be happy to try to reinstall via the methods you mention. The plug is currently part configured and I'd rather start with a blank canvas. I've not used it for months and have been happier using my PogoPlug (with Arch Linux). I'm sick of seeing the GuruPlug sat doing nothing and so I'd like to get it all reinstalled, factory default, and find a use for it. No doubt this will become a bit of a project (replace fan, fit external PSU, etc) and therefore I do not wish to spend £30 on top of this... Indeed, if there was a second hand market for GuruPlug's it'd have probably gone there but as it appears they are not very desirable so it seems the best way to get use out of it is for myself...

You mention two methods - (1) Serial console, (2) U-Boot. Which (out of (a) U-Boot, (b) Kernel, (c) RootFS) can be reinstalled using methods (1) and (2)?

Can you please link to an example of the item I would require for approach (1)? You mention a £5 USB to 3v3 serial adapter.

Can you please give instructions (or a link to instructions) for using methods (1) and (2) to reinstall (a), (b) and (c) above?

Thank you!

[Confusticated]

Serial console is the option I would (in the past have had forced on me to) use.
It also enables a degree of debugging, and easy modification of the uboot environment to correct any errors preventing the kernel from booting Linux.

All the information you need is available on the web in a more complete form than I could post, most of it here (this forum), some on plugcomputer.org, the rest google can find.
All flashing can be done from within u-boot itself, even updating u-boot.

Here are a few pointers...

USB to Serial 3v3 Adapter & Guruplug UART port pinout

google it (omit 'guruplug' from any searches) - 'lots' of embedded devices have been hacked this way for years, or go straight to the openwrt.org forum and search there.
I purchased my no-brand USB Serial Adapter online via ebay (I believe it was advertised as being for a Sony Ericcson Phone).
The difficult step is connecting it to the guruplug, I have still been unable to source the proper connector (after cutting off the phone one .
NOTE: make sure you buy a 3v3 adapter and not a 5v one (which will blow your guruplug up).

kwuartboot - this may enable you to recover should the plug become bricked (search this forum).

References for 'how' and 'what' to flash with u-boot can be found on this or plugcomputer.org.
eg http://www.newit.co.uk/forum/index.php/topic,1810.msg5118.html#msg5118

[LavaChild]

Thank you once again!

It seems that the cable you mention is the Nokia (and clones) DKU-5 and CA-42. Lots of them available at the usual places for a few £s. It would appear the connector is a Molex PicoBlade, available from the likes of Farnell.

This seems like a good option and for <£5.00 I should be able to get to the Marvell prompt and get the plug back to a known state... And then I'll still be left with the spare cable should the need arise again (... and assuming I don't make a habit of messing with UBoot, I should hopefully never need the JTAG board anyway).

Thanks again for all of your help - You've certainly give me enough to chew on, from which I can search elsewhere. I'll be sure to post back if I cannot find the information needed elsewhere!

Thanks.

[LavaChild]

Hello again! You mentioned previously that "it can be done from within Linux itself using the mtd-utils". Can you please give further advice on how one goes about doing this?

Is there any way that I can issue the commands within the following thread from within Linux to upgrade the UBoot/Kernel/RootFS?

http://www.newit.co.uk/forum/index.php/topic,1810.msg5118.html#msg5118

Is it possible to do this with fw_printenv and fw_setenv?

Thanks!

[Confusticated]

The first semi-relevant post I stumbled across, there may be better (guruplug) posts for your purpose
http://www.plugcomputer.org/plugforum/index.php?topic=1047.msg6409#msg6409

I suggest you search plugcomputer.org forum regarding this topic, there has been a lot of posts on flashing from within linux.
An evenings reading may help you avoid mistakes (and will certainly help you sleep).

[LavaChild]

Hello again Confusticated,

Thank you for your continuous support! I have researched, beginning with your post, flashing within Linux. I really am not finding the sort of support I was hoping for - Indeed, whether it be by poor searching or simply lack of posted information, I cannot find a better source of information than your link.

However, this means that all results are not entirely suitable for my purpose - maybe they focus on the Sheeva, maybe they don't use the USB approach, any number of things. With this in mind (as well as your advise that flashing within Linux is risky, especially without a JTAG/serial module to hand) I am reluctant to just try and hack my way through this.

I don't suppose you can offer any other help? As it stands, I fear there is no better source of information and in which case I will decide whether to try and get hold of a serial cable or simply find a new owner for the device (and it would be a shame to do this *after* getting the device into a bad way).

Really not sure how to proceed

Thanks.

[Confusticated]

The only option left that I can think of is to pay someone else to carry out the reinstall for you.
You could email Jason to see how much NewIT would charge, but I suspect the bi-directional carriage may crank up the cost a bit.

Currently a Guruplug Server Plus in original hardware state (unmodified, booting or not, I don't care about the firmware) would be worth around £40 to me as a 'spare'.

[LavaChild]

You've got a PM...