@tekkasit: The latest packages have an updated whitelist that *should* support this, check the latest posts (basically, just replace your linkjail/etc/whitelist file with the one from the latest zip).
@yifanlu: Not really sure what to do about the 3.1 on a K2 stuff, though. Does it install the default 3.1 otaup script (and thus needs to be jailbroken more or less like a proper 3.x device), or a more friendly patched version, or does it automatically install a 3.1 aware jailbreak? ;p
I'm assuming it'll end up only accepting update packages targeted at the host model, not the target (ie. you'd have to use packages targeted at a k3g on your k2i target if you used a k3g as host), or am I wrong?
(If I'm not making much sense, that's probably because I've been up reading all night, and it's now 7AM here, sorry