I just have managed to 'dual boot' into nickel or koreader by adding few lines to /etc/init.d/rcS.
Now if I want to boot into koreader, I only need to touch when it loops with blinking squares, for nickel, just do nothing. Mis-touches can be solved using koreader's home button.
Now without fmon (and KSM, which uses fmon), both readers work like a charm.
I've pasted the modified rcS here in case anyone has the same problem
http://pastebin.com/4VnWgN4R
The modified parts are line 131, and lines 167+.
p.s. the 6 sec in line 168 is a magic number.