NIOS IDE 1.1 to 5.0 upgrade q.

I'm looking at moving from IDE 1.1 to IDE 5.0

purely to fix the IDE 100% cpu lockups in the eclipse CDT indexer.

I work purely on software for a product - I don't use quartus/sopc builder at all.

So, my question is... can I upgrade to NIOS IDE 5.0 and the new system libs (incl. LWIP, LANC9111 ucos, HAL) without rebuilding or altering the existing NIOS 'hardware' designs we are using, or am I on a hiding to nothing...?

So far, I've rebuilt the software under 5.0, and when I dowload it it runs fine until the LAN91C111 initialization completes, at which point it seems to just reset the CPU...

- Roddy