TFTP boot using DNS

[Harald Seiler]

Hi Valerio,

On Thu, 2022-12-15 at 10:27 +0100, Valerio Nappi wrote:
> Hello everyone,
> 
> Context:
> I'm new to the u-boot project. I am trying to boot a Zynq SoC from an
> internal TFTP server, but i have no guarantee that the IP of the
> server is going to stay the same. A DNS service is offered, and kept
> updated.
> 
> When i try to update the serverip variable using the dns <myserver>
> serverip command, the variable seems updated (in the sense that I can
> print the new value) but it is not. Apparently this is ignored on
> purpose at this line of the source [1]. Commit fd3056337 that
> introduced this change, mentions "Don't update the variables when the
> source was programmatic, since the variables were the source of the
> new value.", that is not true in this case, in fact the source of the
> new value is the DNS service.
> 
> Is there a particular reason why this usecase was not forseen?

Unrelated to your point about proper support for this usecase, but maybe
you can use the following as a workaround in the meantime?

	tftp ${loadaddr} ${serverip}:path/to/file

Also adding Joe on CC as he authored the commit you mentioned.

-- 
Harald