I assume you use dhcp to give the client a IP.
If not i would be surprised to find the mac address in the install.inf file.
So on my SLES11 SP1 installations ( via pxe/dhcp & tftp for the kernel ) the key still exist in the install.inf.
The file is located in /var/lib/YaST2/install.inf after the installation and in /etc/install.inf during installation
BTW:
Also check that the initrd has the "tftp" program available. Its looks like tftp is not available on the standard initrd so i assume the protocol type tftp can not be used by autoyast.
In case nothing helps:
You could use a rule.xml to determine the mac address, fetch the xml from A HTTP server to a local directory and do a final "merge"
In case a tftp client is available you could use the logic for pure tftp .
Example ( Not working ):
$ cat rules.xml
<?xml version="1.0"?>
<!DOCTYPE autoinstall SYSTEM "/usr/share/autoinstall/dtd/rules.dtd">
<autoinstall xmlns="http://www.suse.com/1.0/yast2ns" xmlns:config="http://www.suse.com/1.0/configns">
<rules config:type="list">
<rule>
<custom1>
<script>
## Get mac Address
eval mac=$( cat /etc/install.inf | grep -i ^hwaddr | cut -f2- -d":" | tr -d: )
# Get install Server/Autoyast parameter
eval ayast=$( cat etc/install.inf | grep -i | cut -f2- -d":" )
# Download via curl or wget
wget ${ayast}/$mac.xml > /tmp/$mac.xml
echo -n $mac
</script>
<match>*</match>