I haven’t tried the nucs yet with the svn trunk yet, but I did have an issue with them using 1.2.0. They were getting stuck at the ipxe initializing devices. It was having a problem configuring the realtek nic.
I was tried to boot legacy mode (since uefi did not work well with 1.2.0). If I remember correctly I had to update the bios to the latest version. Then on the NUCs I was using in the advanced bios setting there was a compatibility mode. On the one I was using there was linux, win7, win8. I had to set the bios to legacy boot, I think enable legacy roms, and select win7 mode. Save and exit the bios, then POWER IT OFF. If I did not power it off after making the changes it will continue to get stuck at the ipxe initializing devices. By accident I powered it off and then after that it started working. I should have another one in about 2 weeks where I can try them again to see if they are any better with the svn trunk version.