Interesting as initial dhcp request is backgrounded. Please provide very specific details on how pendrive from CorePlus was created? dd, unetbootin, tc-install, or ? Typically on any boot time access to a usb device generally requires a waitusb=5. Do you have such in your pendrive boot parameters?
After I read yoshi314`s post:
Booting stick on the PC connected to the  dhcp network blocked without any message.
After removing "quiet" boot option, I noticed that  system is waiting for relatively long time  in the text mode  for establishing network connection.  
i am sometimes experiencing this on a system which has issues with r8169 network driver. r8168 driver is more stable for this particular hardware, but AFAIK it requires a manual build. the behavior is hard to connect to any specific software configuration.
I analyzed dmesg from my PC installation  and noticed just what yoshi314 said - problem with r8169  driver which temporarily  blocked on  
     eth0: link down   
     etho: link up 
kernel boot phase.
So I can very gladly say  that problem I had is not concerned with 2rc1 release !
With best regards