s2 jumperered -> boot microSD by default?

I want to run off the microSD by default, partly because I’ve screwed up the eMMC, and partly because it’s not large enough to hold a Debian Wheezy image with any logs.

I plan to mount this unit remotely, and don’t want to go there and hold S2 down so it will boot into my environment on the microSD if the power goes out and then comes back. Will it work to just blue wire jumper it and unsolder the switch S2?

Yes, you can add the jumper. Yes you can remove the switch to do that.