Hi Silvia,
for me the Problem is not solved/answered. If WOL is turned of, the unwanted reboot does not occur - that is true. But if you want to use WOL you can not turn it off! It occurs with all different memory configurations I can test with my two 4 GB Kingston memory boards. I don't have others to test. In the meantime I update to the BIOS version 320 - no improvement of the situation. 
I also had the chance to start an Windows installation from a stick. Since I do not have a licence key, I could only choose shutdown in the installation menu: No reboot occurred. So I think it is a problem of the linux kernel, maybe in combination with some memory types and/or bios code... When I want to change the WOL settings with ethtool, it tells me, that pumbg are possible options. With BIOS version 317 I could try to change it from g to another letter, but it remained at the setting g. Now with BIOS version 320 I can change it to the other options (e.g. pum or b) but after reboot I have the magic packet option (g) set again.
Don't you have some experts working on the linux kernel?
Regards,
Christian