[U-Boot-Users] Download of kernel Image through Serial Line.

wolfgang.grandegger at bluewin.ch wolfgang.grandegger at bluewin.ch
Wed Jan 29 11:51:17 CET 2003

>-- Original Message --
>From: Christophe.LINDHEIMER at fr.thalesgroup.com
>To: u-boot-users at lists.sourceforge.net
>Subject: [U-Boot-Users] Download of kernel Image through Serial Line.
>Date: Wed, 29 Jan 2003 10:38:13 +0100
>Just a beginner with U-Boot.
>In my new project we are trying to use Linux and U-Boot.
>The main problem I have is that I don't have any ethernet link on this card.
>- Is it possible to configure U-Boot to make a download of the image using
>the serial line ? ( tftp over serial line or something like that )
>- If it is not possible would it be a big work ?

You could use kermit binary download. Check for example chapter of our DENX PPCBoot and Linux Guide at 

>- If I eventually manage to launch Linux, is it possible to have NFS over
>serial line ?

This does not sound very promising to me. A root filesystem 
on a JFFS2 or CRAMFS partition might be the better option.

>- What are the minima requests in terms of memory to run Linux ?
>- Minimum Ram Size

4MB or better 8MB.

>- Minimum Flash Size if I don't use NFS ( full embeded application )

4MB. For a resonable 'standard' Embedded Linux runtime 
environment for PowerPC including basic network support 
you need approx. the following space in Flash:

 U-Boot                   : 120 KB
 Linux kernel             : 600 KB
 RAMDisk image            : 1   MB
 Root file-system on JFFS2: 2.5 MB

And development and debugging without network will be 
quite cumbersome, I imagine. A hardware debugger would 
be of great help also for image download. Abatron's 
BDI2000 is a _great_ tool. 

Hope it helps,


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