When upgrading the FPGA on some CellCom/Freespeak basestations using the direct Xlinix tool . The upgrade process can sometimes fail.
There two possible issuesa) USB cable speed 
b) Device ID read error  
a) USB cable speed if you encounter this problem
To program the Xilinx PROM in a Cell-Com / FreeSpeak unit it is necessary to change the speed of the programming tool using Output > Cable Setup and setting the TCK Speed/Baud Rate to 1.5 MHz or less.

Always try this solution first for either failure mode 

























Remember to set the USB cable speed back to 6Mhz afterwards

b) Device ID read error if the Impact program displays "The idcode read from the device does not match the idcode in the bsdl File."The root cause of this is that the device manufacturer changed the Device ID on some variants of the xc18v04 device 
 
A number of factors may cause this bad read, but if the message repeats,even at slower cable speeds options include: 1.       Running an earlierversion of iMPACT (a 2 gigabyte download) or:2.       (if you’re low on timeand just want to try to get the device programmed) it is possible to open C:\Xilinx\13.1\ISE_DS\ISE\xc18v00\data\xc18v04.bsd in Notepad and changethe part number from 0101000000110110 to 0101000000100110, saving the file and restartingiMPACT.OR C:\Xilinx\<Impact version #>\LabTools\LabTools\xc18v00\data\xc18v04.bsd