Boom Powder - Where is Runvald's hut on Island 2
 

I've got the boom powder from the alchemist, but cannot find where I must use it to get to Runvald. Help!

I think it is in the opposite road from the alchemist shop. Not too far from there.

There's a wall of rocks near where you first start on that island.

You're absolutely right — the entrance to Runvald in Skyrim, where you use the Boom Powder from the Eaglercraft alchemist, is just across the road from the alchemist's camp.