Before you start you need to download a TFTP server application like pumpkin. The download link is here.
Once you have it Create a folder on your desktop and download the firmware bin you require, the bin's are here. Make sure once you have downloaded this recovery file that you rename it snom(phone version).bin. eg: snom300.bin
Once you have pumpkin installed, link the folder which contains the recovery firmware so that it can be uploaded to the device from pumpkin.
Ensure all the yellow settings are as they are in the image above.
Next we need to find the IP address of the PC we are using as the TFTP server. You can do this by typing ipconfig in command prompt.
No we need to reboot the phone, make sure that press the tick button when you see the screen below:
Once you have pressed the tick you should see a screen that asks you to enter an IP address. I have entered one below:
Once entered, press the up arrow and you should now be able to enter the IP address of the TFTP server. Please make sure they are on the same subnet:
After these two fields have been populated, you can click the tick button again and this will initiate the transfer. You should see the below screens.
On the phone:
On the PC:
Once that has completed the transfer you will then see the below screens:
Once the image has been fully written, the phone will reboot and get a DHCP IP. From there you can log in and set up te phone as you normally would.
Thats it, good luck.