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

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chemicstry

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Is it possible to make such patch as a Magisk module so that no boot.img patching is required? I'm not too familiar with android modding and wondering if Magisk is loaded at all at this stage? Any help would be very appreciated.
 

alecxs

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I didn't say there is an answer... you can figure out and tell us. btw what do you mean, Magisk is loaded [...] no boot.img patching is required? Isn't that oxymoronic? :)
 
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chemicstry

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I didn't say there is an answer... you can figure out and tell us. btw what do you mean, Magisk is loaded [...] no boot.img patching is required? Isn't that oxymoronic? :)
I meant that I want to apply this modification with just a magisk module (zip).

Currently this modification requires unpacking boot image, modifying ramdisk and reflashing, which I rather not do if there is a way without flashing (magisk module).
 

chemicstry

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It seems that it is impossible to add init scripts via modules: https://github.com/topjohnwu/Magisk/issues/933

My added `.rc` file appears in `/system/etc/init/`, but is not loaded as confirmed by `dmesg`.


The alternative way of patching ramdisk is not as straightforward either, so here is how I got it to work on Xiaomi Note 10 Pro:
1. Get boot.img (mine was from original ROM zip, patched with magisk)
2. Unpack with `magiskboot unpack boot.img`. The `magiskboot` is not in PATH and can be found in `/data/adb/magisk/magiskboot`.
3. Create custom.rc:
Code:
on charger
    exec u:r:magisk:s0 -- /system/bin/reboot
4. Modify ramdisk with `magiskboot cpio ramdisk.cpio "add 0700 overlay.d/custom.rc custom.rc"`.
5. Repack boot.img with `magiskboot repack boot.img`. A new-boot.img will be created.
6. Flash via `fastboot flash boot new-boot.img`.
 
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alecxs

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Thx for pointing out. So all you can do is flashable zip anykernel3 that can applied to from TWRP (I never did but should be possible)
 

HansHeiners

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Hello all, I've been googling and searching for 2 weeks now trying to figure out how to get my Samsung TabS6 Lite tablet to power on when plugged in. I bought it to install into a dash mounted tablet for my car, and this thread eventually got me there. I wanted to say what I did in case it would help others.

First of all, fastboot oem off-mode-charge 0 did nothing for me. I spent a lot of time trying different PCs/Cables/Drivers etc and though I never found exact confirmation, I suspect Samsung just doesn't allow this functionality in their bootloader.

First I'm using the standard rom except with Magisk having it rooted.
In Magisk I had to go into the settings and let superuser be for "Apps and ADB" and I had to reboot.
Then with ADB on my windows PC I could execute "su" in ADB Shell which let me do the rest of this.

ADB Shell commands
su
mount -o rw,remount /
(i couldn't mount the system directory, but I found a helpful tip somewhere that said mount the root and you can write to the system directory.)
cd system/etc/init
(now i have to create a text file. There's probably a lot better ways to do this, but ultimately I did it this way and could be done all through command prompt in windows, essentially we're creating a .rc file that turns off off mode charging.)

cat > off_mode_charge.rc
(this starts the creation of a text file called "off_mode_charge.rc" I don't think the name of the .rc matters just has to be in the init directory and .rc extension, the next line you'll be typing the lines of the .rc file)
# /system/etc/init/off_mode_charge.rc
(thats the first line, then press enter to do the second line)
on charger
(second line)
setprop sys.powerctl reboot,leaving-off-mode-charging
(third line, with 5 spaces, don't know if the spaces matter thats just how it was formatted when I found it on stack exchange)

Then press Control D to end the file. You should now have an .rc file called off_mode_charge.rc in your init directory and this file essentially tells the system to power on when plugged in. Apparently, all the inits are called at bootloader step. The charge animation still comes up at first, but then it will boot there after.

Finally give that file permissions (don't know if this is necessary but I did it and it worked)

chmod 0755 off_mode_charge.rc
chown root.shell off_mode_charge.rc

Finally set the root system to read only again
mount -o ro,remount /


And that along with a Tasker script to shutdown the tablet when it loses charge has it working for me. I'm just posting this as guest as I'm not a contributor here but I found a lot of this through a combination of
android.stackexchange.com/questions/20021/automatically-power-on-android-when-the-charger-is-connected/221384#221384

and the information posted here.

This is the only method that worked for me, as all the files mentioned in this thread don't exist on my system. Thank you so much!

My Device: Asus Transformer Pad TF300T
Rom: KatKiss ROM Nougat 7.1 Release by Timduru
This is a AOSP-based rom -> maybe works for other AOSP-based roms as well?

Good to know: You don't even need an PC for this, you can complete all steps with the App "Total Commander" directly on the device.
 
Hello all, I've been googling and searching for 2 weeks now trying to figure out how to get my Samsung TabS6 Lite tablet to power on when plugged in. I bought it to install into a dash mounted tablet for my car, and this thread eventually got me there. I wanted to say what I did in case it would help others.

First of all, fastboot oem off-mode-charge 0 did nothing for me. I spent a lot of time trying different PCs/Cables/Drivers etc and though I never found exact confirmation, I suspect Samsung just doesn't allow this functionality in their bootloader.

First I'm using the standard rom except with Magisk having it rooted.
In Magisk I had to go into the settings and let superuser be for "Apps and ADB" and I had to reboot.
Then with ADB on my windows PC I could execute "su" in ADB Shell which let me do the rest of this.

ADB Shell commands
su
mount -o rw,remount /
(i couldn't mount the system directory, but I found a helpful tip somewhere that said mount the root and you can write to the system directory.)
cd system/etc/init
(now i have to create a text file. There's probably a lot better ways to do this, but ultimately I did it this way and could be done all through command prompt in windows, essentially we're creating a .rc file that turns off off mode charging.)

cat > off_mode_charge.rc
(this starts the creation of a text file called "off_mode_charge.rc" I don't think the name of the .rc matters just has to be in the init directory and .rc extension, the next line you'll be typing the lines of the .rc file)
# /system/etc/init/off_mode_charge.rc
(thats the first line, then press enter to do the second line)
on charger
(second line)
setprop sys.powerctl reboot,leaving-off-mode-charging
(third line, with 5 spaces, don't know if the spaces matter thats just how it was formatted when I found it on stack exchange)

Then press Control D to end the file. You should now have an .rc file called off_mode_charge.rc in your init directory and this file essentially tells the system to power on when plugged in. Apparently, all the inits are called at bootloader step. The charge animation still comes up at first, but then it will boot there after.

Finally give that file permissions (don't know if this is necessary but I did it and it worked)

chmod 0755 off_mode_charge.rc
chown root.shell off_mode_charge.rc

Finally set the root system to read only again
mount -o ro,remount /


And that along with a Tasker script to shutdown the tablet when it loses charge has it working for me. I'm just posting this as guest as I'm not a contributor here but I found a lot of this through a combination of
android.stackexchange.com/questions/20021/automatically-power-on-android-when-the-charger-is-connected/221384#221384

and the information posted here.
Hi @leahcimx , I'm here in Feb23 also trying to re-purpose a Galaxy Tab A ( SM-T295 ) into a piggyback head unit to drop onto my Volvo C70. I'm an newbie to Tasker/Autoinput and drafting a task to auto-shutdown, but I'm here looking for support to set up the device to auto-start on USB power. I've got a very rough grasp of doing adb commands on a PC but not smart enough to take it further and in need of spoonfeeding assistance to get me over the line. Can you or anyone else reading help me ???
Thx
 
sure.. where is the spoon stuck now?
Hi, OK status of now is I have TWRP and root & Magisk etc and believe I need to swap out a file 'lpm' in system/bin folder. I'm able navigate there using the TWRP explorer and make a copy of the file plus rename to lpm.old.

The area I've fell short is the ability to either edit the copied lpm , or create a new lpm....so I need support to get a replacement lpm file dropped into system/bin. This is either by recommending a file editor/creator app and giving me appropriate script to copy/paste into the file.

..then was there another element regarding setting file permissions?
 

alecxs

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but that requires you to modify system. I wouldn't go that far. you can try the method described in post #207 first. for this I recommend to unpack magisk_patched.img with AIK and add the .rc file in overlay.d
 
but that requires you to modify system. I wouldn't go that far. you can try the method described in post #207 first. for this I recommend to unpack magisk_patched.img with AIK and add the .rc file in overlay.d
erm...that #207 post is a foreign language to me.

As with most things reading a total newb, its never clear whether the action is on the device..or on a pc connected to the device.

What you've said in one sentence is probably perfectly clear to someone who knows what they are doing...but then theres me...:-/

Can you break this down into babysteps that a geriatric like me can follow?
 

alecxs

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on PC, extract Android.Image.Kitchen.v3.8-Win32.zip and drag & drop your magisk_patched.img onto the unpackimg.bat
 

alecxs

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if you don't have magisk_patched.img on PC, you can create TWRP backup of boot partition and use the boot.emmc.win from TWRP/BACKUPS/
 

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    managed to sort it cheers, The only thing I couldn't work out is why it wouldn't restore with TWRP it kept saying failed under restored :-( I did however manage to restore it with fastboot and it is working great cheers, i will have 10 to do is there a way i can take a back up of my stock rom with all the apps installed and restore this or is it best to just do each separately, sorry if its not in the right post
    1
    for anyone with tab acitve 2, this was the steps i used.
  • 19
    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 :)