I had no problems during em-core flashing.
I DID follow the instructions to the letter !
(Like you ALWAYS should when firmware-flashing is involved..)
AFTER : The main-problem is that you no longer have the original firm-ware partition .
When I connect my emcore/rockbox Classic to a Mac .. It offers to initialize the disk !
It does however work fine under windoze !!
Battery-life : I play only lossless files and I'm getting about 18 hours playtime if I don't shuffle to much
and have had no problems with charging . That's very good IMO, close to original FW-runtime .
If I already had a 5G-iPod I would rather spend the money on buying a CF-card and adapter plus a larger battery .
While the Classic-port does work, there is still a lot left to fix ..