[U-Boot-Users] Protect Flash from tftpboot typos

[Wolfgang Denk]

In message <20040723143731.GA10725 at synertronixx3> you wrote:
>
> I do not find CFG_DIRECT_FLASH_TFTP mentioned anywhere in our
> include/configs/scb9328.h.

-> ls -l include/configs/scb9328.h
ls: include/configs/scb9328.h: No such file or directory

I cannot comment on code I've never seen.

> Is it included by
...
> Otherwise I don't know where else I could have this option enabled.

No, it is not.

> Yeah, thats right. I have to protect our customers to fry their boards, 
> not me :)

Just set up a service to recover these boards, and get rich ;-)

> > Seems you have configured U-Boot like that. On systems for which I am
> > responsible attempts to TFTP to flash will not do harm.
> 
> tftp to flash does no harm. It is the mapped Area which is not protected
> by an default load adress when typos occur.

What is a "mapped area"? 

> Reading this I agree to you unlocking, erasing is not possible on
> increasing adresses. Otherwise IIRC I think the whole block can be
> unlocked and erased on different access adresses inside the block!
> 
> Otherwise how is it possible typos fry the flash device?
> 
> I am using intel 28F128J3...

Your flash driver does not drive the VPEN pin, it seems?

> I think I will replace tftpboot an cp commands for customers by two
> argument less firmware - linux kernel or rootfs - commands.

I don't think this is a good idea.  The  software  should  behave  as
documented,  and U-Boot documentation does not contain such arbitrary
limits (nor do I like them).

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
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