HP battery "bootstrapping"

Hi,
Sadly, I've got a HP pavilion dv2 laptop here that was left with the lithium battery almost empty for too long (maybe 2 to 4 weeks?), to the extent now it doesn't charge normally. The battery was operating normally before that, no signs of reduced capacity. The only thing leading to this seems to have been that it was left at 0% for too long.
A HP battery test tool (Windows only, I wonder if I can get the same information under linux, maybe it's in the verbose output of the acpi utility?) reports that part of the time the voltage is increasing (still well below design voltage, around half of it), but sometimes it will also decrease. I suppose this means sometimes the battery is being charged, but not always.
Does anyone have any idea of how do HP laptops implement the bootstrap charging process? Is there some secret handshake to initiate this in a way that goes on until the battery can be charged normally? Or are voltage drops part of the bootstrapping charge process too?
The battery is removable and if I do that, it'll go back to slowly increasing voltage values, but this is still sub-optimal as it requires constant supervision, to avoid too much of a drop.