LPC1752 UID not in early chips?

[lpcware]

Content originally posted in LPCWare by mozmck on Mon Jan 21 14:35:08 MST 2013
I am reading the UID using IAP in LPC1752 chips, and it seems that the newer chips work fine, but a couple of older chips just return FFFFFFFF for 3 of the numbers and 0 for the first one.  The parts are all revision A, and the date code on the chips that return a valid number is 1215, the older ones that don't work are 1135.

Did the older chips not have a UID, or is there a different way to access it?  I can't find anything that says so.

[lpcware]

Content originally posted in LPCWare by cfbsoftware on Wed Jan 23 05:03:22 MST 2013
"A small batch of LPC175x and LPC176x processors came out of the factory in 2011 without the Serial Number programmed."

For more details see:

http://forums.nxp.com/viewtopic.php?t=5722