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[Q] Power on when plugged in (boot when docked)?

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Nov 19, 2010
11
26
Appologies if this has been asked/answered here before. I tried searching, but didn't find any solution. Maybe someone else has stronger Google skills than I.

Here is what I am trying to do. I'd like to find a way to have the Galaxy Tab power on automatically when it is plugged in to power and begins charging. My company has several Galaxy Tabs (rooted) that are being used for a specialized purpose. They should be plugged in 24/7. However, it is possible that they will lose power, and the battery will eventually run down. When power is restored, I'd like to be sure that they come back on, without any user interaction.

I don't THINK this is the case, but it is worth asking: Is this a standard Android setting I can change anywhere?

I assume I will have to modify some code. Right now, I notice that when the Tab is turned off, and you plug it in, the charging indicator shows up and displays the battery levels. To me this indicates that code is running SOMEWHERE as soon as the Tab gets plugged in. I'd like to hijack that, and just have it power on.

Does anyone know where I should start looking for the code that runs when the device is plugged in? I found a charging.jpg in /mnt/.lfs that seems to be the image that displays, but so far no sign of what code is running. If there is any sort of init script, that would be amazing if someone could point that out.

Even if you don't know how to accomplish this, if you have any helpful pointers or "take a look at these files" to point me in the right direction, I'd really appreciate it.

As always guys, thanks for all the help!
 
Nov 19, 2010
11
26
SOLVED: Power on when plugged in (boot when docked)?

Hey guys, I know that no one else may ever have any use for this, or even care, but I wanted to post an update. I was finally able to get this figured out through some guess work, trial and error, and looking at the work someone else did on a fairly similar project.

I owe plenty of credit to the fine work done by Chainfire on his project described in this link. His work, while not the same project, demonstrated that something similar to what I wanted to do WAS possible.

Anyway, to make the tablet boot up when first plugged in- The battery charging indicator that runs when you first plug in the Galaxy Tab is run from the file /system/bin/playlpm. To make it boot automatically, delete the old playlpm (or better yet, rename it to playlpm.bak, just in case) and replace it with the following script.

/system/bin/playlpm
Code:
#!/system/bin/sh
/system/bin/reboot

Be sure to set the ownership and permissions the same as the old playlpm. It didn't work for me at first because I had forgotten to give execute permission.

Thats all that it takes. Most of the time, the Tab should have enough power to go straight to booting. If the battery is really dead, it may flash the charging battery icon a few times, failing to boot until it gets enough charge. It will eventually come on.

I don't know of any additional side-effects for doing it this way, but there may be some, I don't know what else the stock playlpm is supposed to manage. This worked for my purposes though. Hope it could help someone else.
 

RickyLan

Member
Jul 7, 2006
27
0
Hi DavidThompson256,

Just want to say thank you for your research, I've been looking for the same thing a few months and just discovered your post.

I thought it is something to do to the kernel but looks like this simple mod can do the trick.

Thanks again!
 

prscott1

Senior Member
Nov 5, 2007
807
23
Houston
Ironically, I have an opposite problem. My phone automatically reboots when plugged in. My searching led me to your post. I installed the nomoarpower app but I could get it to keep my pad turned off. LOL
 

dhoai

Member
Sep 3, 2011
6
0
Did you have to root the tab before making this change?

Thinking about picking up the Galaxy Tab Plus but need it to do the same thing and boot when the power is plugged in.
 

knownchild

Senior Member
Dec 7, 2007
117
5
An update?

I have cm9 how do i find the file for my gsii?

there is no such file as the one you speak for my device, how did you find what file yours was?
 

Decert0

New member
Jan 6, 2013
1
0
As many others I dont have this file on my galaxy tab II

But i do have the kernel doing someing when pluged in when the device is not powerd on. First it tryed to show the splash img and then starts the charing animation. Does anyone know where this script is launched on a galaxy tab 2 7"?
 

rasssta

Member
Aug 11, 2010
6
0
Thank you! Been looking like a mad person for a solution like this for a couple of days and only found NoMoarPowah, which didn't fit my needs. :D
 

luuma

New member
Mar 26, 2013
1
0
on the s6500

thanks, this was really helpful. I've got this working on the Samsung Galaxy s6500 (mini 2), and I had to make a small addition to the script:

Code:
#!/system/bin/sh
su
/system/bin/reboot

Hey guys, I know that no one else may ever have any use for this, or even care, but I wanted to post an update. I was finally able to get this figured out through some guess work, trial and error, and looking at the work someone else did on a fairly similar project.

I owe plenty of credit to the fine work done by Chainfire on his project described in this link. His work, while not the same project, demonstrated that something similar to what I wanted to do WAS possible.

Anyway, to make the tablet boot up when first plugged in- The battery charging indicator that runs when you first plug in the Galaxy Tab is run from the file /system/bin/playlpm. To make it boot automatically, delete the old playlpm (or better yet, rename it to playlpm.bak, just in case) and replace it with the following script.

/system/bin/playlpm
Code:
#!/system/bin/sh
/system/bin/reboot

Be sure to set the ownership and permissions the same as the old playlpm. It didn't work for me at first because I had forgotten to give execute permission.

Thats all that it takes. Most of the time, the Tab should have enough power to go straight to booting. If the battery is really dead, it may flash the charging battery icon a few times, failing to boot until it gets enough charge. It will eventually come on.

I don't know of any additional side-effects for doing it this way, but there may be some, I don't know what else the stock playlpm is supposed to manage. This worked for my purposes though. Hope it could help someone else.
 

chtc2005

New member
Dec 4, 2007
2
0
Thank you. I have a galaxy tab p1000 in my car, with your help my tab will automatic turn on when engine start , it completed amazing :). Thanks again.

IMG_20120506_100742.jpg
 
Last edited:

thompsos

Senior Member
Jul 18, 2007
149
95
Dallas/Ft Worth, TX
I made one minor tweak to the code, as follows:

Code:
#!/system/bin/sh
sleep 20
/system/bin/reboot

This makes the program wait 20 seconds between recognizing that the device is plugged in before issuing the reboot command. This helps ensure my device has enough juice to actually start, hopefully on the first try but if not, then on the second.

You can adjust the sleep length as desired - see here: http://www.cyberciti.biz/faq/linux-unix-sleep-bash-scripting/
 

XTDragonHawk

Member
Nov 9, 2009
10
2
I tried to install this app on my Galaxy Tab P1000. (Official Android 2.3.6 - rooted)
I always got the error message "202 - not enought space on /system ..."

So I installed MIUI V5 and MIUI V4 on my Tab.
I was able to install the app on both ROMs.
But both of them are not working properly.

If I turn off my device, it shows me the "new" battery info.
One second later, the display is getting darker.
One more second later, the display is turned off.
I am also not able to click on "reboot now".

(the timer option is working fine. I can set it to 2330 and the Tab will start at this time)

I want to use my Tab in my car instead of the built-in radio.
So I need that app getting working! :D

Please tell me which ROM u're using and which kernel :)

I'd be happy if someone else could help me with my problem :)
 

chtc2005

New member
Dec 4, 2007
2
0
XTDragonHawk said:
I tried to install this app on my Galaxy Tab P1000. (Official Android 2.3.6 - rooted)
I always got the error message "202 - not enought space on /system ..."

So I installed MIUI V5 and MIUI V4 on my Tab.
I was able to install the app on both ROMs.
But both of them are not working properly.

If I turn off my device, it shows me the "new" battery info.
One second later, the display is getting darker.
One more second later, the display is turned off.
I am also not able to click on "reboot now".

(the timer option is working fine. I can set it to 2330 and the Tab will start at this time)

I want to use my Tab in my car instead of the built-in radio.
So I need that app getting working! :D

Please tell me which ROM u're using and which kernel :)

I'd be happy if someone else could help me with my problem :)

Check pm, hope that can help you some.
 

majzok

New member
Oct 26, 2009
3
1
I have galaxy tab 2 p3100, replaced /system/bin/playlpm with given code, but after i plug charger nothing happens: just charging icons like always.
Anyone have idea how to fix this?
 

annlee

Member
Sep 1, 2013
21
1
Granada
play.google.com
I have galaxy tab 2 p3100, replaced /system/bin/playlpm with given code, but after i plug charger nothing happens: just charging icons like always.
Anyone have idea how to fix this?

Same problem here, did all the process including the correct permissions etc.. and appear battery stucked and then dark blue screen.

I am using samsung galaxy trand, as happens to your galaxy tab 2, seems our OS version 4 does something before playlpm or does not work, or am I wrong?

please help
 

BlancScha

New member
Oct 31, 2013
3
0
Petaling Jaya
auto power off when unplugged, and wont switch on

Its seems like my tab is crazy!

After installing cm 10.1 cdesai.zip my tab is currently having problems with data provider, debug mode,and now its seem to
Getting more worst!!! :'(

I can't use my tab unless I plug in the charger, or else it won't switch on! When unplugged it,my tab auto shut down and won't turn on until u press the power on button and quickly connect the charger...

(using it now with charger on!! :'( ) if there's anyone know what's the real problems here pls HELP ME!! and pls share with me how to stock back from cm10.1 to GB STOCK??? I really feel so desperately now!! :'(

Thanks in ADVANCE!!!
 

majzok

New member
Oct 26, 2009
3
1
Same problem here, did all the process including the correct permissions etc.. and appear battery stucked and then dark blue screen.

I am using samsung galaxy trand, as happens to your galaxy tab 2, seems our OS version 4 does something before playlpm or does not work, or am I wrong?

please help

I got it working on tab 2. Here what I did:
1. Install stock 4.0.4
2. Install NoMoarPowah! apk
3. edit file like in first post
 
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SadamHu

Member
Aug 15, 2012
14
1
Hi there, I'm a noob! I have a rooted Galaxy Note (first one), how do I write this script? Do I have to make a file and inside the file just write that text in there? And is that all I have to do to make my phone autoboot on charge?
 

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  • 18
    SOLVED: Power on when plugged in (boot when docked)?

    Hey guys, I know that no one else may ever have any use for this, or even care, but I wanted to post an update. I was finally able to get this figured out through some guess work, trial and error, and looking at the work someone else did on a fairly similar project.

    I owe plenty of credit to the fine work done by Chainfire on his project described in this link. His work, while not the same project, demonstrated that something similar to what I wanted to do WAS possible.

    Anyway, to make the tablet boot up when first plugged in- The battery charging indicator that runs when you first plug in the Galaxy Tab is run from the file /system/bin/playlpm. To make it boot automatically, delete the old playlpm (or better yet, rename it to playlpm.bak, just in case) and replace it with the following script.

    /system/bin/playlpm
    Code:
    #!/system/bin/sh
    /system/bin/reboot

    Be sure to set the ownership and permissions the same as the old playlpm. It didn't work for me at first because I had forgotten to give execute permission.

    Thats all that it takes. Most of the time, the Tab should have enough power to go straight to booting. If the battery is really dead, it may flash the charging battery icon a few times, failing to boot until it gets enough charge. It will eventually come on.

    I don't know of any additional side-effects for doing it this way, but there may be some, I don't know what else the stock playlpm is supposed to manage. This worked for my purposes though. Hope it could help someone else.
    5
    Appologies if this has been asked/answered here before. I tried searching, but didn't find any solution. Maybe someone else has stronger Google skills than I.

    Here is what I am trying to do. I'd like to find a way to have the Galaxy Tab power on automatically when it is plugged in to power and begins charging. My company has several Galaxy Tabs (rooted) that are being used for a specialized purpose. They should be plugged in 24/7. However, it is possible that they will lose power, and the battery will eventually run down. When power is restored, I'd like to be sure that they come back on, without any user interaction.

    I don't THINK this is the case, but it is worth asking: Is this a standard Android setting I can change anywhere?

    I assume I will have to modify some code. Right now, I notice that when the Tab is turned off, and you plug it in, the charging indicator shows up and displays the battery levels. To me this indicates that code is running SOMEWHERE as soon as the Tab gets plugged in. I'd like to hijack that, and just have it power on.

    Does anyone know where I should start looking for the code that runs when the device is plugged in? I found a charging.jpg in /mnt/.lfs that seems to be the image that displays, but so far no sign of what code is running. If there is any sort of init script, that would be amazing if someone could point that out.

    Even if you don't know how to accomplish this, if you have any helpful pointers or "take a look at these files" to point me in the right direction, I'd really appreciate it.

    As always guys, thanks for all the help!
    4
    Hello,

    None of the proposed solutions worked for me on Samsung Galaxy Tab A 10.1 (T580) with Android 7 (no boot, black screen, boot to Recovery, etc.), but after much testing, I've found another way to make it work.

    Extract boot.img from the rooted device and copy to PC (13540000.dwmmc0 -> T580's boot partition):
    adb shell "su -c dd if=/dev/block/platform/13540000.dwmmc0/by-name/BOOT of=/sdcard/boot.img"
    adb pull /sdcard/boot.img

    Download Android Image Kitchen:
    https://forum.xda-developers.com/showthread.php?t=2073775

    Drag-and-drop boot.img to unpackimg.bat.

    Open ramdisk/init.rc

    Search for on charger and add at the end (after write /sys/class/power_supply...):
    setprop ro.bootmode "normal"
    setprop sys.powerctl "reboot"

    Save file and repack image (double click on repackimg.bat).

    Rename image-new.img to boot.img

    Tar boot.img file (you will need tar for Windows):
    tar -cf boot.tar boot.img

    Download Odin latest version:
    https://samsungodin.com/

    Open Odin, click on AP, select boot.tar file.

    Reboot device to download mode:
    adb reboot download

    Click Start on Odin.

    After reboot, disconnect and power off device. Reconnect the USB cable and wait.
    2
    I think I'm in the same boat as @fritz.barnes. I've tried every combination of suggestion here but there's something weird going on.

    I have a Samsung Galaxy Tab A 10.1 (2019) with unlocked bootloader, TWRP, and root (Magisk).

    It appears as if anytime i replace /system/bin/lpm and put in the suggested shell scripts to trigger a reboot, it appears this isn't running at all or incurring some kind of exception.

    I was initially really confused because there were other people saying that the script appeared to be working but that it was booting them into recovery/TWRP, and that appeared to be what was happening to me. But after going through so many scenarios, I think there was a reason for that.

    1. When I first made the change to /system/bin/lpm after being in USB debugging and from ADB shell, when I turned the tablet off with cord unplugged, then plugged in cord, I got stuck at the initial lightning charge screen that doesn't have the real battery %, etc.
    2. When this just got stuck forever and didn't reboot (regularly or into TWRP), I held POWER + VOL DOWN to reboot, then POWER + VOL UP to get back into TWRP. After getting into TWRP, mounting system, and making the similar changes to /system/bin/lpm, it "appeared" to be working in that after powering off with cord unplugged, it would start up when cord plugged in but go immediately into TWRP.
    3. I realized later after trying multiple different versions of this file that all kept going into TWRP, if I rebooted regularly into system first with TWRP, then powered off with cord unplugged, then plugged cord in, I was still stuck at the initial lightning charge screen that doesn't have the real battery %, etc.

    After all that, I'm assuming the initial lightning charge screen has nothing to do with /system/bin/lpm, and that this shows regardless of what /system/bin/lpm is. But compared to the original /system/bin/lpm behavior of in a few seconds showing correct battery %, my attempts at the shell script /system/bin/lpm probably just appear to be doing nothing (not rebooting) and just keeping me at the initial lightning charge screen.

    As I said, I tried multiple different versions of the script throughout this thread and nothing has seemed to work. I have created the file or copied the file in different ways and also verified EOL characters, etc.

    Does anyone have any idea what's going on with my situation (and possibly with @fritz.barnes having the same or similar issue that I do) or how to debug this? Is there something that has been altered with reboots by TWRP that requires any sort of Android property to be set or anything? I'm not an Android developer, but I see this in the TWRP source in terms of doing a system reboot, but I'm not fully sure what's going on here.

    Code:
    case rb_system:
    			Update_Intent_File("s");
    			sync();
    			check_and_run_script("/sbin/rebootsystem.sh", "reboot system");
    #ifdef ANDROID_RB_PROPERTY
    			return property_set(ANDROID_RB_PROPERTY, "reboot,");
    #elif defined(ANDROID_RB_RESTART)
    			return android_reboot(ANDROID_RB_RESTART, 0, 0);
    #else
    			return reboot(RB_AUTOBOOT);
    #endif

    Thanks!

    ---------- Post added at 09:48 PM ---------- Previous post was at 09:21 PM ----------



    Not sure if I'm normally supposed to reply to my own post here, but I have some more information that seems interesting.

    If I take the original /system/bin/lpm, make a copy and then use the copy as /system/bin/lpm (and move the original to a different file, i.e. /system/bin/lpm.bak), the copied version of the original binary also seems to not work and keep me at the initial lightning charge screen. I am making sure to chmod 0755 and chown root.shell any copied files as you can see below. The original file has timestamp of 2008-12-31, and this specific file appears to be the only one that will work (and go to the normal charge indicator screen).
    aFwCp4k.png


    Not sure if this will further help diagnosis anything, but what's going on here? Why with a copy of the original lpm binary does this also result in me being stuck at the initial lightning charge screen? Any ideas?

    I'd be willing to send a $50 bounty via Venmo to whoever can help me get this working.

    from my own experience, if something get stuck, it means the comand in tge lpm file is wrong, you have to try different command.

    i have successfully auto boot 4 different phone, S4, Mate 7, zenphone6, redmi 6a, they all need to use different command, eventhough i only changing the same file. in my case in init.rc and some by just changing kpoc file.

    Sent from my Redmi Note 7 using Tapatalk

    Hi guys, as a followup after trying again tonight it is working!

    I came across a different link where someone posted his "one-liner" for doing this:
    mount -o remount,rw /dev/block/platform/dw_mmc.0/by-name/SYSTEM /system && cp /system/bin/lpm /system/bin/lpm_orig && echo "#!/system/bin/sh\n/system/bin/reboot" > /system/bin/lpm

    As mentioned previously, with me using Magisk users have reported "/system" mount not existing.

    What it looks like it boils down to at least for me, is that every time I was trying this, I was doing a move/rename of the original /system/bin/lpm, then creating a new /system/bin/lpm (as root/root) and then doing a chmod 0755 and a chown to root/shell. Apparently this method did not work for me even though I was seemingly left with the same file with same permissions, but looks like since this person's one-liner does a copy to backup original /system/bin/lpm and then just overwrites the existing file contents with the simple shell shell script to auto-boot, this works!

    I'm not sure if my situation is related to Magisk or what, I'm just not very familiar with Android mounts/partitions/etc. but if anyone is having a problem similar to mine, replacing contents of existing file worked for me.
    2
    Found solution that works on Samsung Galaxy Tab A6

    For me the reboot scheme didn't work but what did work was putting into /system/bin/lpm this:
    Code:
    #!/system/bin/sh
    echo b > /proc/sysrq-trigger

    Hope it helps someone :)