Had this happen to me as well and got it to work by doing the following below.
Download the Hellix 2.71 firmware Flash Memory directly from line6.com
https://line6.com/software/index.html
And from searching thru the Line 6 Device Factory Procedures I came across this for the HX Effects which worked for the Stomp.
If you run into any trouble with a failed update or your unit will not boot up, try powering on while holding the right arrow ">" This will put the unit into update mode and you can re-install the latest firmware from there.
After powering on the unit while holding PAGE> button I opened up the Line 6 Updater and choose Offline Mode at the bottom, selected the HX Stomp, and then updated via the firmware .hxf file I downloaded directly form Line 6. Did the reboot again and got it back working.