How to change MAC address on RPI-B?

[John W. Kitz]

Reiner,

My remarks are based on this example:

"autoload=no
ethaddr=12:34:56:78:99:aa  <===
fdt_high=ffffffff
serverip=192.168.1.130
bootargs=earlyprintk console=ttyS0,115200
boot_tftp=dhcp; tftp 0x46000000 arch/arm/boot/uImage; tftp 0x49000000
arch/arm/boot/dts/sun7i-a20-cubieboard2.dtb; bootm 0x46000000 - 0x49000000 
uenvcmd=run boot_tftp"

which I found in this http://linux-sunxi.org/UEnv.txt article and a bit of
documentation that is being referred to in it, which can be found here
https://www.kernel.org/doc/Documentation/kernel-parameters.txt.

> So when doing so the locally administered MAC address is passed on 
> from uEnv.txt to the O/S during boot and is then used to override the 
> globally

I didn't think, that it will be passed from the U-Boot Enviroment settings.
You can set the MAC address, but the FreeBSD kernel shows always the unique
MAC address.

JKi: Please note that my remarks weren't intended to be a statement, rather
a question.

> unique MAC address or does the O/S check both the information found in 
> its configuration files and what is configured in uEnv.txt before 
> configuring and activating the network interface(s)?

Which configuration files do you mean? AFAIK there is only the FDT blob.
I guess it ignores the setting in uEnv.txt.

JKi: Also please note that I have no experience using an ARM based board at
this time. I've only ordered one recently.

> Makes me wonder which of the two (i.e. locally administered through 
> uEnv.txt or locally administered through the O/S) takes precedence.

Only the unique MAC address and the locally administered MAC address, will
take affect.

JKi: Looking at the email exchange on this topic I thought it was
established previously that this can't be true.

> In addition this might affect configuration decisions when one would 
> want to configure a device for net booting (at least when browsing 
> through what can be configured by means of uEnv.txt I believe that was 
> one of the options I
> saw) through uEnv.txt?

Regards, Jk.