2850 tftp command issue

[Neil]

Hello

whilst doing tftp boots it anything goes wrong with the boot that causes the 
tftp to prompt the bcm is unavailable.  

Could not find kernel image: blah
boot:
Could not find kernel image: blah
boot:
Could not find kernel image: blah
boot:
(at intervals coverned by the pxelinux timeout variable)

during this time any commands result in 

Error(0xa1):Connection Timeout.

If I go to the physical console and fix the boot, say by correcting the label, 
all starts up again 

keyboard input does not work across sol so a visit to the machine, either to 
fix the boot or reboot, is required

Can this be worked around or fixed?

Neil