[2011-09-14 12:43:24] <Sicelo> to disturb a little: i am using h-e-n with the latest booston script. connecting an externally powered hub (not for charging) i always get VBUS OVERVOLTAGE - You just fried your N900. at least the port is still fine any ideas?
[2011-09-14 12:48:56] <Sicelo> i am connecting the hub to N900 soon after i turn VBoost On
[2011-09-14 12:52:40] <DocScrutinizer> Sicelo: this indicates your externally powered hub feeds back a somewhat too high voltage to the N900 USB port
[2011-09-14 12:53:57] <DocScrutinizer> Sicelo: I had to look up in bq24150 datasheet what exactly VBUS overvoltage means, I guess it gets triggered on >6V or sth
[2011-09-14 13:04:06] <DocScrutinizer> VBUS ABS MAX -0.3 .. 20 V
[2011-09-14 13:04:39] <DocScrutinizer> (3) The bq24150/1 family can withstand up to 10.6 V continuously and 20 V for a maximum of 432 hours.
[2011-09-14 13:05:18] <DocScrutinizer> ABS MAX for other chips' pins connected to VBUS is way lower though
[2011-09-14 13:06:39] <DocScrutinizer> recomended operating conditins: VBUS Supply voltage, VBUS min:4 max:6 Volt
[2011-09-14 13:07:26] <DocScrutinizer> (1) The inherent switching noise voltage spikes should not exceed the absolute maximum rating on either the BOOST or SW pins. A tight layout minimizes switching noise.
[2011-09-14 13:11:18] <DocScrutinizer> VBUS(OVP) Overvoltage protection threshold for boost (VBUS pin) Threshold over VBUS to turn off converter during boost min:5.8 nominal:6 max:6.2 V

The "you just fried your N900" part is a bit of tongue-in-cheek, but honestly you shouldn't gamble with it. Anyway I don't give any warranty on N900 actually being fried when this error notification pops up ;-D