Bootloader - How does it know what partition to boot

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Hello.

I am looking at fixing powerdown from TWRP on the Galaxy Note2 series of phones. I was able to get it to power down calling android_reboot(ANDROID_RB_POWEROFF, 0, 0); from libcutils. However when the phone powers on, it goes straight into recovery.

I was hoping someone might have an idea on where the bootloader gets it's information on what partition to boot so we can fix this to boot into system right away.

On the qualcomm Note1, we could run

echo 3 > /dev/block/mmcblk0p12

to boot into system.

I am looking forward to your ideas.

Maybe this can help you?
https://github.com/CyanogenMod/andro...s/sec-reboot.c

Originally Posted by Rebellos

Maybe this can help you?
https://github.com/CyanogenMod/andro...s/sec-reboot.c

Hi, thanks for the pointer. Do you know how to pass the info to that sec reboot function to boot normally?

Re: Bootloader - How does it know what partition to boot

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Based off a quick glance at the code from my phone you want to hit the reboot_mode_none case.

Sent from my SCH-R950 using Tapatalk 2

Originally Posted by thewadegeek

Based off a quick glance at the code from my phone you want to hit the reboot_mode_none case.

Sent from my SCH-R950 using Tapatalk 2

Yeah I was wondering how to pass that to some place from userland since you can't talk to the kernel without some facility interface.

Originally Posted by bigbiff

Yeah I was wondering how to pass that to some place from userland since you can't talk to the kernel without some facility interface.

Ah ok my bad, misunderstood the question. Beyond my are of expertise though.

Originally Posted by thewadegeek

Ah ok my bad, misunderstood the question. Beyond my are of expertise though.

I don't have my phone now to list running modules, but I am wondering if there is a module that might handle this. I will investigate tonight.

Originally Posted by bigbiff

I don't have my phone now to list running modules, but I am wondering if there is a module that might handle this. I will investigate tonight.

btlock.ko
cifs.ko
commkm.ko
dhd.ko
dns_resolver.ko
md4.ko
mvpkm.ko
pvtcpkm.ko
scsi_wait_scan.ko
vpnclient.ko

CyanogenMod 10.1.