Hmmm... not sure how to do that 
Example?
But with your suggestion to run WinScp, and @psherman's input above, here's what I did in case someone else like me (with less knowledge of OpenWRT, SSH, etc.) might overcome accidentally installing a SnapShot:
- Download the latest stable build SysUpgrade BIN for your Router (in my case R6900v2 here). Note: I tried the "Factory Image" which is a n.IMG file but it did not work.... needed the BIN.
- I renamed the file for ease of use later to: OpenWrtSysupgrade.bin
- Download & Install then Run WinSCP:
File Protocol: SCP. Host Name: 192.168.1.1. Port 22. Username=root. PW=blank - Copy the BIN file you downloaded to the /tmp folder of the Router
- Open a Windows Command Prompt
- Type in: ssh root@192.168.1.1
- It may respond with a warning first time (proceeded)
- Type in: sysupgrade -n -v /tmp/OpenWrtSysupgrade.bin
- Answer prompts as needed
- It installs the BIN file and reboots the router.
- Try logging in from a browser to: 192.168.1.1
I've used FreshTomato for a while... now it's time to dig into OpenWRT !
Hope this helps someone in the future!