You could telnet into the box if it booted up far enough, but usually for boot problems you have to connect to the console port directly and this shows you the OS boot process, modules loaded etc.
The iStor firmware seems to work perfectly, at least on our 2 Axstor boxes.
No problems connecting with any initiators that I've tried software or hardware, including Microsofts.
It's your call really, our Axstors are all but decommissioned now and hold only duplicates of data held elsewhere.
That said, I had no problems when upgrading to the iStor firmware, but it's always best to have a backup just in case.