Sorry, I was miles away from computer last week... Unfortunately that time I did not find any app for this purpose on the market, so decided to write my own. The main request was to make it available for multiple users from different locations (we co...

Hi,The reason of becoming a TFTP address invalid on the phone is not known (based on TAC's answer) , however there are 2 workaround I could recommend:If you have access to a computer on the same LAN where the affected phones are, install a TFTP serve...