We have about 20 RB260GSP deployed, most running 1.15 but some running 1.14. I upgraded one of them from 1.14 to 1.17. It still responds to pings, powers devices as before & the VPN settings seem to be intact, but instead of the Web GUI it just serves a blank page: not even an HTML tag. No way to manage it now. Cycling power does not help.
Upgrading the rest of our switches is halted until we get to the bottom of this. Has anyone else had this problem?
We have tha same situation. Only tftp recovery helped. O course after recovery you have to configure it like a new one… 
Wait: SwOS has tftp/bootp recovery? Why didn’t I know this?!
Same trouble with 260GS.
I was able to recover the more recent of the two with the procedure here.
Unfortunately, my earlier entrant into the “dumb switch” category never gets to the point of blinking the “ACT” LED, and never attempts to retrieve the firmware. Apparently even its recovery boot code is fried. So, I’ll keep using it as a test bench switch, where the default configuration is all it needs. At least I can put one back into production!
I tried to use netinstall but it can’t detect sw260.
Now it work with TFTP.
Thank you very much.
You may not asked about it 
?