Try to upgrade CME 3.3 to 4.1
Anyone has experience during upgrade image, thats tell you the size is too big for TFTP, please increase the block size. I change the setting at tftp, but it is still same thing.
I have to copy the image to USB flash driver and stick into 2800 series router.
Then I copy from USB to flash.
Actually, it happened to me a few times already. I Thought it is my tftp problem, but couple friends of mine has same problem.
I use PumpKIN or solarwinds tftp.