[U-Boot-Users] Verifying checksum problems.

Wolfgang Denk wd at denx.de
Mon Feb 28 21:10:03 CET 2005

In message <OFC0BE6659.AF54EF2D-ON85256FB6.006C6C07-85256FB6.006DD828 at optovia.com> you wrote:
> We load our kernel at 1 MB. We load our associated ram-disk at 2MB. This 
> ram-disk is currently 6.2MB compressed. 

Why are you doing this? Did you check  how  big  your  _uncompressed_
images  will  be?  Did you try to try to figure out what happens when
U-Boot actually uncompresses the kernel image?

> However since the increase in the size of the ram-disk we have encountered
> the following error. After the kernel and ram disk are loaded to their 
> respective locations and we use
> "bootm 100000 200000" , this is what happens.

And this doesn't ring a bell to you? Did  you  try  out  higher  load
addresses,  like 0x200000 for the kernel and 0x400000 for the ramdisk

> The checksum is verified for the kernel and it is decompressed  and 
> everything is fine. 
> It however fails in the ram-disk checksum verification. We get a checksum 
> error.

> However if we move the ramdisk load address to an area above 8MB everthing > 
> works fine. If we load it at 7MB we see the same error. 

Well - what are you complaining about then? Isn't it obvious that the
Linux kernel, when being uncompressed, overwrites your ramdisk  image
which was loaded at a too low address?

> Since our earlier ram-disk at 5.8 MB worked we surmise that something is 
> corrupting the area between 7.8MB and 8MB. Following the sequence of 

I don't think so.

> Is by any chance this area being used or is there some other explanation? 

Yes: it's a user error - using a too low load address.

> As I said earlier if the ram-disk is loaded at 8MB or above everything is 
> currently okay.

I bet it's also OK if you load it at 3 or 4 MB.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Objects in mirror are closer than they appear.

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