I'm going to throw out a few more comments on this because I just had 3 phones that did the exact same thing.
I ordered 8 refurbs - 1 advance and 7 standards. Took the advance out of the box and hooked it up - expected it to come up to the configuration screen and it stayed on initializing unless I powered it up with no network connection. Screwed around with it for 4 hours, all the while cussing out the IT folks for some unseen network change.
Pulled a standard out of the box and spent the next 4 hours screwing with that. Both phones I went through and did factory resets on them as part of my troubleshooting procedures (cuz they were used and may have had bogus settings in them).
Now, and hour past my exit time, and fully pissed off I pulled out a 3rd one - boing! Fired right up, no problems.
Out of the remaining 5 phones I found one more with the same problem, and the other 4 were fine.
The 5 that fired up had OS and bootloaders all over the spectrum so it was not a software thing.
My verdict now: If the phone is stuck in initializing, regardless if it gets POE power from the LAN, and regardless if it says Checking Link and succeeds and the happy light flashed on the switch, the network interface is bad and you should send the phone back where you got it or scrap it without screwing around.
Loading software is fine, and I'm going to flash all mine before I roll them out, but you can't load software if the phone never gets a DHCP network connection (or otherwise) to allow you to do it!
