Date   : Sat, 27 Nov 2010 09:35:03
From   : mfirth@... (Michael Firth)
Subject: [BeebSoc] Killing Linux - but how?

On 27/11/2010 17:20, Rick Murray wrote:
> Hi,
>
> I have a Neuros OSD which is basically an MPEG4 video recorder based 
> around a TI ARM+DSP SoC. [I won't describe it here, it's on my b.log 
> if you're interested - just search for OSD]
>
> What I would *like* is to be able to load a replacement firmware. If I 
> am able to do this, then I can see about drawing a big smiley face on 
> the video output. This, while serving no actual purpose, will permit 
> an exercise in bringing up the system.
>
> Now, the box itself supports uboot and is capable of TFTPing an image 
> into memory, however I am not keen on this approach because:
>   1. The Neuros-supplied serial lead is "back to front". I don't recall
>      the genders offhand, but the plug won't go into the PC's serial
>      port because they're both the same gender. Hence a back-to-back
>      will need to be constructed on a bit of veroboard (I say vero
>      because I don't know if it needs to be a crossover or not).
>
>   2. Because it is a serial link, it requires another PC, the LAN, and
>      VNC...
>
>   3. The use of "uboot" is "destructive". In other words, I am NOT able
>      to restore normal behaviour by power-cycling the unit. I would need
>      to go back into uboot and reconfigure its options, and hope like
>      hell I don't screw it up. [= instant brick]
>
<snip>

Why should the use of U-boot be destructive?

Normally, if you interrupt U-boot's startup you can then load a new 
image into RAM with TFTP and execute it, without overwriting anything on 
the flash.

Or is it that the Neuros doesn't usually run U-boot, so you can't 
install it without having to erase part of the startup sequence?

Regards

Michael