[TUT] How to use fastboot on our device

Search This thread

laufersteppenwolf

Inactive Recognized Developer / Retired Forum Mod
Jul 1, 2012
2,840
6,964
Baden-Württemberg
droideveloper.com
As you can see in the title, i decided to write a small fastboot tut, especially for our p880 and its "own" commands and tricks ;)
I am, as always, not responsible for what you do with your device. Do it on your own risk.

I will however not explain on how to set up fastboot on your PC. There are tons of tuts out there on xda, just search for it ;)
NOTICE: You need an unlocked bootloader for this

Screenshots will be added later, 'cause my lappy is compiling right now and i thought i could use the time to write this ;) so just wait a bit

Now, lets begin with the fun, shall we? :D

General

Fastboot is usually quite easy to use. But if you went searching for a tut on the web, you might have noticed that it doesn't work the way it should on your device.
That's because LG messed something up in the bootloader, but let's don't worry about that now, it does work nontheless ;)

Fastboot is "a part" of the bootloader. This means, neither the kernel (boot), nor the recovery gets booted.
That gives you the ability to flash, but also boot kernels/recoveries. And yes, i meant booting, without really flashing it :p


Now we need to get into fastboot mode:

And this is (one of) the point(s) where LG messed up. The usual command is "adb reboot bootloader". But this command does not work on your device the way it should.
It gets you into a kind of fastboot mode, but you can't flash anything, because it says the bootloader would be locked, even tho it isn't.
The working command is
Code:
adb reboot oem-unlock
i guess this command sounds familliar, doesn't it? :p and don't worry, it will not lead you to a menu that deletes your data.
It will lead you to the working fastboot mode ;)

now we're in the working fastboot mode. To check if you've set up fastboot correctly, type
Code:
fastboot devices
this should list your phone and its serial number.

It is recognized? good. so now we might want to check the status of our device (BL unlock state, serial number,...).
Therefore type
Code:
fastboot getvar all
now you can check whether it's really unlocked or not.

If everything's fine, you might want to...

Flash something

In order to flash something, you need the appropriate image. For kernels it's mostly "boot.img"
The command to flash something via fastboot is in general
Code:
fastboot flash <partition> <filename>

Example: You want to flash a kernel (named test_boot.img) and you have downloaded the kernel to the folder where your fastboot.exe is.
So you type
Code:
fastboot flash boot test_boot.img
This will copy the kernel to your device and then flash it to the LNX (boot) partition.

Of course you can flash other partitions, too, like system, data, cache, recovery...

After a flash, it is wise to clear the cache, or even your /data partition...

Deleting a partition

You don't need a recovery to wipe a partition, just use fastboot ;)

The general command is
Code:
fastboot erase <partition>

For our example it's enough to wipe the cache. You can do this using this command:
Code:
fastboot erase cache

Also here you can wipe all partitions, like system, data, cache, boot, recovery...

So now we've flashed what we wanted to, wiped the needed partitions, but how do i..

Get out of fastboot


This is as easy as getting in ;) just type
Code:
fastboot reboot
to reboot the device (Here's another thing, where LG messed up.... it reboots, but stays at the LG spash screen.
So press the power button for at least 10 secs. Now your device will reboot into recovery (!?) :confused:
then just tap reboot system now and be happy ;) )

or
Code:
fastboot continue
this one will not reboot the device, but continue the boot procedure. I, for one, would suggest you to use the first command

now your device will boot up normally (except your kernel/system.... has a bug of course :p )

for more help, just type
Code:
fastboot help

and the last point is...

Bricking the device
nah, just kidding :p
 

Cheetah1024

Senior Member
Jun 19, 2012
321
59
Internet. I live on the Internet.
So, to get into fastboot mode, I have to turn on my phone, plug it to my computer and in cmd I type adb reboot oem-unlock, right? Is there any possibility to access it in case of a bootloop or something?
 
Last edited:

laufersteppenwolf

Inactive Recognized Developer / Retired Forum Mod
Jul 1, 2012
2,840
6,964
Baden-Württemberg
droideveloper.com
A little update from LG...

I wrote them that they have messed up our bootloader, and told them the bugs/problems/... well, see yourself:

1) "adb reboot bootloader" doesn't bring me into bootloader. Well it does, but even though i have unlocked the bootloader, it still says it would be locked.
instead i need to use "adb reboot oem-unlock" to get into bootloader.

- P880 does not support "adb reboot bootloader" to go into bootloader. P880 only works "adb reboot oem-unlock" instead of "adb reboot bootloader" to go into bootloader. and then you can use the fastboot command mode after accept unlock bootloader.



2) "fastboot reboot" partly reboots the device, but then it keeps stuck at the first LG splash screen. pressing power button for 10 seconds brings me into recovery then, instead of into the ROM.

- P880 supports "fastboot reboot", before flashing the customize image, "fastboot reboot" reboot normally.



3) "fastboot flash system [path/to/system.img]" gives me "fatal error: unknown partition"

- P880 can only flash boot, recovery. Ex> fastboot flash boot/recovery boot.img/recovery.img



4) "fastboot boot [...]" doesn't work at all.

- P880 does not support "fastboot boot [...]" command

- P880 supports only flash, erase, reboot as you already seen in bootloader unlock warning message.



5) I have found no way to boot into fastboot/bootloader without a booting phone. Maybe you could try to add the possibility to boot directly into fastboot.

- You can only go into fastboot mode using "adb reboot oem-unlock"
 
  • Like
Reactions: arararagi

arararagi

Senior Member
Jan 13, 2013
473
688
Yeh, you need to kdz flash if you mess up both system and recovery.
Keep an suid busybox in /data so you can root and re-flash CWM/TWRP in the backup+restore mode without having to clear data so the stock ROM can boot.
 

baxtex

Senior Member
Oct 16, 2011
1,107
116
Can't seem to get his wokring properly, think it's the drivers.

I connect my phone to the pc, run cmd and I reboot it to to the bootloader. From there, I can't do anything. I i Write "fastboot devices" I get nothing, can't flash anything either. Have tried the official drivers from lg, but it doesn't work.
 

olokos

Recognized Developer
Oct 16, 2011
2,945
2,494
Warsaw
That's the same way of using fastboot like it is on Sony devices, you should mention it so more people would use this guide. :)
The only difference is that on sony devices if you want to unlock your bootloader you need to get the key from this site and then fastboot 0x0fce oem unlock 0xKEY
 
Last edited:

gesaugen

Senior Member
Oct 5, 2009
91
6
ppl, i beg for help:
when I use adb reboot oem-unlock or adb reboot bootloader, my phone only resets itself and boots back into normal working mode. I've tried to boot it into bootloader with holding volume up and power button and it boots into some kind of mode wheres only picture with symbols of mobile with symbols of data cable and power cable being plugged into phone with red symbol over cables that they shouldn't be unplugged. I've also tried eboot oem-unlock and reboot bootloader commands in that mode and it only resets the phone back into normal working mode while command fastboot flash recovery twrp.img only gave me "waiting for the device" and nothing happening...

also I've entered into hidden menu with 3845#*880# command bit there's no "BL status" or "Bootloader Unlock Check" or anything that has any connection to Bootloader

help?
 

InterrtuptoR

Senior Member
Jan 24, 2015
189
40
I tried this method and for fastboot devices
i get no permissions fastboot
pls help
edit: i just did it with sudo fastboot devices

but i have another error:
fastboot flash zimage zImage
sending 'zimage' (4913 KB)...
OKAY [ 1.216s]
writing 'zimage'...
FAILED (remote: Invalid Partition Name.)
 
Last edited:

csk1jw

Senior Member
Apr 1, 2014
397
1,037
InterrtuptoR said:
but i have another error:
fastboot flash zimage zImage
sending 'zimage' (4913 KB)...
OKAY [ 1.216s]
writing 'zimage'...
FAILED (remote: Invalid Partition Name.)

Only "boot" and "recovery" are supported for fastboot flash command. Boot is the kernel and takes boot.img. Unfortunately, "system" is not supported, otherwise developing on this phone would have been similar to Nexus devices.
 

Top Liked Posts

  • There are no posts matching your filters.
  • 28
    As you can see in the title, i decided to write a small fastboot tut, especially for our p880 and its "own" commands and tricks ;)
    I am, as always, not responsible for what you do with your device. Do it on your own risk.

    I will however not explain on how to set up fastboot on your PC. There are tons of tuts out there on xda, just search for it ;)
    NOTICE: You need an unlocked bootloader for this

    Screenshots will be added later, 'cause my lappy is compiling right now and i thought i could use the time to write this ;) so just wait a bit

    Now, lets begin with the fun, shall we? :D

    General

    Fastboot is usually quite easy to use. But if you went searching for a tut on the web, you might have noticed that it doesn't work the way it should on your device.
    That's because LG messed something up in the bootloader, but let's don't worry about that now, it does work nontheless ;)

    Fastboot is "a part" of the bootloader. This means, neither the kernel (boot), nor the recovery gets booted.
    That gives you the ability to flash, but also boot kernels/recoveries. And yes, i meant booting, without really flashing it :p


    Now we need to get into fastboot mode:

    And this is (one of) the point(s) where LG messed up. The usual command is "adb reboot bootloader". But this command does not work on your device the way it should.
    It gets you into a kind of fastboot mode, but you can't flash anything, because it says the bootloader would be locked, even tho it isn't.
    The working command is
    Code:
    adb reboot oem-unlock
    i guess this command sounds familliar, doesn't it? :p and don't worry, it will not lead you to a menu that deletes your data.
    It will lead you to the working fastboot mode ;)

    now we're in the working fastboot mode. To check if you've set up fastboot correctly, type
    Code:
    fastboot devices
    this should list your phone and its serial number.

    It is recognized? good. so now we might want to check the status of our device (BL unlock state, serial number,...).
    Therefore type
    Code:
    fastboot getvar all
    now you can check whether it's really unlocked or not.

    If everything's fine, you might want to...

    Flash something

    In order to flash something, you need the appropriate image. For kernels it's mostly "boot.img"
    The command to flash something via fastboot is in general
    Code:
    fastboot flash <partition> <filename>

    Example: You want to flash a kernel (named test_boot.img) and you have downloaded the kernel to the folder where your fastboot.exe is.
    So you type
    Code:
    fastboot flash boot test_boot.img
    This will copy the kernel to your device and then flash it to the LNX (boot) partition.

    Of course you can flash other partitions, too, like system, data, cache, recovery...

    After a flash, it is wise to clear the cache, or even your /data partition...

    Deleting a partition

    You don't need a recovery to wipe a partition, just use fastboot ;)

    The general command is
    Code:
    fastboot erase <partition>

    For our example it's enough to wipe the cache. You can do this using this command:
    Code:
    fastboot erase cache

    Also here you can wipe all partitions, like system, data, cache, boot, recovery...

    So now we've flashed what we wanted to, wiped the needed partitions, but how do i..

    Get out of fastboot


    This is as easy as getting in ;) just type
    Code:
    fastboot reboot
    to reboot the device (Here's another thing, where LG messed up.... it reboots, but stays at the LG spash screen.
    So press the power button for at least 10 secs. Now your device will reboot into recovery (!?) :confused:
    then just tap reboot system now and be happy ;) )

    or
    Code:
    fastboot continue
    this one will not reboot the device, but continue the boot procedure. I, for one, would suggest you to use the first command

    now your device will boot up normally (except your kernel/system.... has a bug of course :p )

    for more help, just type
    Code:
    fastboot help

    and the last point is...

    Bricking the device
    nah, just kidding :p
    2
    InterrtuptoR said:
    but i have another error:
    fastboot flash zimage zImage
    sending 'zimage' (4913 KB)...
    OKAY [ 1.216s]
    writing 'zimage'...
    FAILED (remote: Invalid Partition Name.)

    Only "boot" and "recovery" are supported for fastboot flash command. Boot is the kernel and takes boot.img. Unfortunately, "system" is not supported, otherwise developing on this phone would have been similar to Nexus devices.
    1
    fastboot boot <kernel> <ramdisk> -c "androidboot.mode=normal"

    <kernel> is the kernel zImage
    <ramdisk> can be a .img, .cpio, .cpio.gz

    -c "androidboot.mode=normal” is needed the get the kernel booted for the p880 with the correct commandline

    Gesendet von meinem LG-P880 mit Tapatalk 4 Beta
    1
    A little update from LG...

    I wrote them that they have messed up our bootloader, and told them the bugs/problems/... well, see yourself:

    1) "adb reboot bootloader" doesn't bring me into bootloader. Well it does, but even though i have unlocked the bootloader, it still says it would be locked.
    instead i need to use "adb reboot oem-unlock" to get into bootloader.

    - P880 does not support "adb reboot bootloader" to go into bootloader. P880 only works "adb reboot oem-unlock" instead of "adb reboot bootloader" to go into bootloader. and then you can use the fastboot command mode after accept unlock bootloader.



    2) "fastboot reboot" partly reboots the device, but then it keeps stuck at the first LG splash screen. pressing power button for 10 seconds brings me into recovery then, instead of into the ROM.

    - P880 supports "fastboot reboot", before flashing the customize image, "fastboot reboot" reboot normally.



    3) "fastboot flash system [path/to/system.img]" gives me "fatal error: unknown partition"

    - P880 can only flash boot, recovery. Ex> fastboot flash boot/recovery boot.img/recovery.img



    4) "fastboot boot [...]" doesn't work at all.

    - P880 does not support "fastboot boot [...]" command

    - P880 supports only flash, erase, reboot as you already seen in bootloader unlock warning message.



    5) I have found no way to boot into fastboot/bootloader without a booting phone. Maybe you could try to add the possibility to boot directly into fastboot.

    - You can only go into fastboot mode using "adb reboot oem-unlock"