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

[Wolfgang Denk]

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

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

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