Using "save" in u-boot is really pretty safe. It only unprotects and
writes to sector 1, which is where u-boot stores its env vars -- it
doesn't overwrite u-boot code at all. Worst case if it were to corrupt
sector 1, u-boot will detect this when it CRC's sector 1 before loading
the env vars, and it'll just fallback to its compiled-in default vars.
At which point a new "save" will just write those out to sector 1
I regularly load kernels from MMC w/out writing them to flash by using
more or less the process described already in this thread. I also
regularly use "loadb" to achieve a similar thing but loading the kernel
over serial instead of from an MMC card (a lot slower, but more
flexible when I'm working remotely and don't have physical access to
the MMC card).
On Aug 11, 2004, at 9:04 AM, Kim Hendrikse wrote:
>> I tested the following for you.
>> I changed the bootcmd via
>> set bootcmd fatload mmc 0 a2000000 uimage\;bootm a2000000
>> This appears to me to boot the image on the mmc card.
>> This does erase the flash sector 1 to save the enviorment so I am not
>> sure if it is as safe as you think. Of course you don't have to save
>> enviorment but typing in the set bootcmd.. every time can be tedious.
>> The image copied to fat always seems to be lowercase filename.
> Ok, this is great! I don't mind risking it once, but every time is a
> of a worry. I'll still building a new chassis for my stick so I can't
> it yet. But this looks good. Well... I may even be tempted to typing
> the above command every time until I've verified my new home made jtag
> cable :)
> - Kim
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