I also had problems with the JLime bootloader executable downloaded from the JLime project side. The kernel could not mount the root partition although it was a stock ext2 as described in the documentation.
After some search I found the following webpage
http://www.acetolyne.net/Projects/node/17#JLime
There is a newer kernel and the corresponding modules. With that one, I can now boot into Linux on my HP Jornada 720.
Note: I am not affiliatet with the folks on acetolyne.net. I also have no clue how's the relationship with the JLime project.
Edited by cvjb 2015-07-07 10:18 AM