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Community Council | Posts: 4,477 | Thanked: 11,213 times | Joined on May 2012 @ Southerrn Finland
#8
Originally Posted by badpixel View Post
It's only semi-true and only when phone is in developer mode.
Typical phone user, uses phone as-is, doesn't play with developerbmode, open mode or ubiboot.
And off-the-shelve Nokia n9 (or after clean flash) doesn't boot up automatically after connecting USB cable), until you enable developer mode(I was told there that's root cause, not open mode).
I'm sorry to tell you but you are wrong there; the same boot problem with empty battery exists for stock devices too, it is not only a problem of developer mode or open mode.

When the battery of a N9 goes so flat it cannot boot up in "act dead mode" when you plug in the USB cord it will not be able to charge.
The HW of the device is designed so that it needs the kernel to be minimally alive to be able to switch on the charging logic, there is no HW charging support at all in the device.
Hence, for a totally dead device you have to use the flasher trick to revive it, even on totally non-modified closed-mode device.

The way the flasher charging works, is it injects a very low-power-consuming kernel (called the APE algorithm) into the device that turns no peripherals on and hence is able to run on the USB juice alone. This kernel then starts the charging process.


Originally Posted by badpixel View Post
Another one problem is ubiboot, it's normal kernel, but with limited userspace(lacks bme/charging support), and by default it boot ups to eecovery mode, after connecting USB cable.
You can change thst behaviour of ubiboot in theory in config file, but it only covers clean harmattan shutdowns and works a bit like loterry (sometimes it worked only with stock ooen kernel, sometimes only with kernel plus), and only cold boot(doesn't work after dead battery).
Yes, the ubiboot kernel has no charging support which is too bad. Hence when you run a device long time with ubiboot, for example when doing a backup dump of the device it will deplete the battery during the operation.
For that reason you should not attempt such without a full battery.

I am sorry I have neglected ubiboot for a long time; as N9 is not currently my daily driver device I have been very lazy with it!
However, I started to study it again some time ago, so maybe I'll get one day to the point of adding the charging support to ubiboot kernel.

I also have an idea of integrating the APE algo fatureset in the ubiboot so you'd be able to boot an empty device up without the flasher trick but I'll see if I get to do that someday


Originally Posted by badpixel View Post
So all these annoyances shouldn't be problem for average jo^H^Hn9 user. The problem isn't directly in how stock n9 behaves, but with TMO sect, which owns most of harmattan devices and uses them in non-conventional way. So the problem exis in "us", we(TMO members) are mental and nothing can fix that ;-)
As you say, ubiboot does have the configuration option of loading up the 2nd level kernel in "act dead mode" when USB charger is plugged into a non-powered-on device; however as I explained above it is not enough to help if the battery is totally dead; it has to have a tiny amount of juice left.
When ubiboot does this, it has to anyway boot up 2 times and this eats up some of the weak battery; first time the ubiboot kernel boots, and then it kexecs to the Harmattan kernel with ACT_DEAD flag set on kernel command line.
 

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