Can't boot Freerunner without battery - Was: Re: unable to start up freerunner after batterie was full down

Yorick Moko yorickmoko at
Tue Jul 15 18:13:11 CEST 2008

Werner has submitted 10 patches.
It should no longer be a problem

On Tue, Jul 15, 2008 at 6:09 PM, Steven **
<montgoss+openmokocommunity at> wrote:
> I assume this is planned, but I'll go ahead an say it.
> I think the Freerunner should have a software feature to detect when
> the battery is critically low and shutdown.  Ideally, the boot process
> would also check the battery and refuse to boot(or at least require
> override) if the battery charge was below the critical mark.  This
> would prevent the state where you have a dead battery and no way to
> charge it.
> Either this feature or the ability to boot from USB is a must for the
> end-user software load.
> I personally had no plans to buy extra batteries or external chargers.
>  I would hate to have to should I lose track of my charge status and
> screw myself.
> -Steven
> On Mon, Jul 14, 2008 at 11:12 AM, Al Johnson
> <openmoko at> wrote:
>> The phone can't take >100mA from USB without asking, and the PMU enforces
>> this. The AC PSU can supply more than this, as can most USB ports, but at
>> this stage of the process the checks to see if this is available can't be
>> done so we're limited to 100mA. When the old uBoot powered up the assorted
>> chips the current would spike higher than 100mA which was fine with battery,
>> but without battery the PMU would cut the power to stop violation of the USB
>> 100mA limit. The new uBoot changes the power up sequence to try to keep the
>> current below 100mA at all times. That's a rough outline anyway - full
>> discussion in the kernel list archive.
>> On Monday 14 July 2008, Steven ** wrote:
>>> The battery can delivery more power than the AC USB adapter?
>>> -Steven
>>> On Mon, Jul 14, 2008 at 1:18 AM, Joerg Reisenweber <joerg at>
>> wrote:
>>> > Am Mo  14. Juli 2008 schrieb Steven **:
>>> >> Perhaps it's been said before and I missed it...  But why can't the
>>> >> Neo boot off USB power alone?
>>> >
>>> > Boils down to sth like powering up a whole town after blackout.
>>> > All components drawing a spike of energy same moment, which USB can't
>>> > deliver. ->next blackout.
>>> > Werner's new U-boot extenuates this somewhat, but as much of this is
>>> > inside PMU hardcoded, SW can't do much.
>>> >
>>> > /jOERG
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