I've got two boards here (I don't know how extensive this is yet) reporting the QUAL field in DID1 as 0 which indicates an engineering sample according to the datasheet.
DID1 = 0x1020602C
I don't think I'm misinterpreting that although that would be the nicest explanation.
IC is marked as
980 YF
TM4C1230
E6PMI
4BA9NTW
G4
Robert
BTW, forcing the chip part number to the front of the title is rather annoying.
