[U-Boot-Users] tftpboot question

[Jerry Van Baren]

eagle keeper wrote:
> Hi all, and sorry for disturbing you again.
> I'm trying to load an image from a tftp server using tftpboot.
> Server is reachable, and running. Address of image is correct.
> U-boot contacts the right IP, then tries to load the image and intead
> of printing "#" as documented, prints "T" (it means timeout I
> suppose).
> But I continue getting an error message: "Retry count exceeded"
> Then the procedure starts again.
> 
> What this behaviour can depend from?
> I excluded tftp configuration problems and network problems.
> 
> Thanks in andvance

I would suspect your ethernet receiver is having problems with larger 
packets (probably a hardware configuration issue).  I don't know what 
processor you are using, but a classic problem is that short packets 
(pings) work because the packet fits entirely in the ethernet FIFO 
buffer, but long packets (tftp data) break because the ethernet FIFO 
cannot buffer the whole packet and the at-speed store to SDRAM is broken 
(cannot keep up with packets of length 1500 or so bytes and/or SDRAM 
bursting is broken).

gvb