Checksum Error @ Copy TFTP FLASH

[Circusnuts]

I am trying to download IOS into a 2500 & I am getting success on the TFTP Server, but the router fails the image on the Checksum...    Verifying checksum...  invalid (expected 0x555, computed 0x7688)   Any Ideas...  I have swapped FLASH sticks & this did not change the outcome.  These are Cisco FLASH sticks (not a compatibility issue).  The image is not too large for the amount of FLASH.  The boot ROM's are of the newest model 11.0's.  I installed new RAM, but I've not reached RAM operations @ this point in a 2500 (verifying what has just been installed into FLASH)...   Any leads would be greatly appreciated...   Thanks !!! Phil