OS4.1 won't run on Efika and I don't think there are any plans for an Efika version.
While the Efika has a low price, there are a few downsides. There only one 44 pin IDE which can't be split and you are pretty much limited plugging a 2.5" drive right into it. If you want a CD/DVD drive or another HD they have to be connected to one of the USB 1.1 ports where they'll be limited to 1.5 Megabytes p/s. There is no free PCI slot once you've installed a GFX card and 128MB Ram will soon seem like a tiny amount.
