[U-Boot-Users] Question about CFG_ENV_ADDR during RAMBOOT

Wolfgang Denk wd at denx.de
Tue May 22 23:04:05 CEST 2007

In message <46535865.6060400 at smiths-aerospace.com> you wrote:
> Looks to me like it would be better defined:
> #define CFG_ENV_SIZE		0x2000

No, this is broken as CFG_ENV_SIZE may be (and often actually is)
smaller than CFG_ENV_SECT_SIZE

> The saving grace here is probably:
> * For a RAMBOOT image, there isn't any incentive to save lots of stuff 
> in the env since it (generally) disappears on a reboot and definitely 
> disappears on a power cycle.

One could argue that a correctly  configured  ramboot  version  would
access  the  original  copy  of  the  environment  in flash. But such
discussion is void, as ramboot itself it not supported officially.

> * On the PowerPC, at least, the first 12K of u-boot.bin is the HRCW and 
> vectors which aren't used by a RAMBOOT image so overwriting them is a 
> non-fatal error.

Wrong. You may have timer and other interrupts,  so  overwriting  the
exception vectors is a Bad Thing (TM).

Best regards,

Wolfgang Denk

DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
A failure will not appear until a unit has passed final inspection.

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