Some fast help on this would be good, I have been on this problem for 14 hours.
In a Virtualbox test environment I have 2 virtual machines networked together using a internal network (no traffic runs though the host, it is all at a software level). One is a fresh client with 512mb of ram and a dual core set-up, the other is the server with 1.5GB of ram and running server 2008 r2. The server is configured as a dns server, dchp server, domain controller and also serves PXE booting though WDS (Windows Deployment Services). Both machines can see each other and I am able to start a network boot.
The issue comes at the second to last stage of the pre windows PE install. On TFTP download of boot.sdi it starts it but stops during the boot process.
Best Answer
You need more than 512 MBs of RAM to boot a wim. WIM files are RAMdisk files so they need at least as much RAM as the file is big. Look at your WIM file and use that as the base amount of RAM to use with your machine. You should always add buffer space to the VM for processing at boot time. Some configurations are made and the only place to store them in a RAM OS is the RAM.
I add ~ 100 MBs as buffer but you should experiment around to get a good feel for you buffer. You might need more but most likely you would need less.