Develop Bugs

[dev]How to Un/Re/Pack a Boot.blob and unyaff a boot.img

Technically i have to give credit to scott crossler
www.scottsroms.com
for showing me the method
and then i came upon turges
faq
Thanks Turge and Scott and whomever created these blobpacktools
but since i keep getting pms
and im sure you do to
scott
Here are the steps for repacking the boot.img. Some involve running the commands via cygwin, others involve running them via the Windows Command Prompt.
The instructions for installing cygwin, extracting and repacking the boot.img were found here: http://www.freeyourandroid.com/guide...ot-img-windows
Once you have setup cygwin, extract the attached files in a folder under your "home" folder in cygwin.
Also unzip blob tools into the same folder as your boot.blob
1.
Code:
copy boot.blob to the same folder and run the following via
the Windows Command Prompt to extract the boot.img from the boot.blob:
BlobUnpack.exe boot.blob
ren boot.blob.LNX boot.img
which will create boot.img
2.
Code:
From the cygwin bash terminal window,
switch to the same folder and run the following
to extract the ramdisk from the boot.img:
./extractboot boot.img
You now have an out/ramdisk folder
that contains the files you want to edit.
3.
Code:
Once done, repack the ramdisk and kernel into boot_new.img
with the following command (via cygwin once again):
./packboot
4.
Code:
then from the Command Prompt repack boot_new.img
into boot2.blob using the following:
blobpack -s boot2.blob LNX boot_new.img
5.
Code:
You can now flash the boot.blob to the staging
partition via a command in updater-script:
Code:
package_extract_file("/boot.blob", "/dev/block/mmcblk0p4");
or by using adb while in recovery/android:
Code:
dd if=/sdcard/boot2.blob of=/dev/block/mmcblk0p4

Lastly the rundown is like this
if you want to take a ota blob
and extract the contents for a raw base
and a raw kernel
1
take the ota and extract the blob file and place
in your folder with blobtools
2. then run
Code:
blobunpack.exe blob
Which now creates
Blob.APP =System.img (can be renamed system.img and unyaffed in the kitchen)or straight cygwin
Blob.sos=Recovery Img
Blob.Ebt=Bootloader information
Blob.Lnx=kernel (can also just be renamed boot.img and unyaffed in kitchen)
Blob.pt=Partition info
so to repack lets say your custom remade image
and your custom kernel
and a recovery of your choice
run
Code:
blobpack.exe -s blob lnx boot.img sos twrp.blob app system.img
then simply take the blob replace in the ota file
and flash in recovery
and it should flash a rom packed as a blob

Hi!
...also you can flash the new boot.blob via fastboot mode
>fastboot-i 0x0B05 flash boot boot.blob
:good:

Call me stupid, but what does repacking the boot.img do? I never pm'ed you, but what would we gain from this. a lil lost

unpacking a boot.img allows you to take a stock already built kernel
and make specific changes to the ramdisk
more specifically
default.prop
can make kernel insecure
debuggable
bootanimation enabled
blah blah blah
and init.rc
but also
cardhu
and goldfish.rc
and init.trace
and init.usb
then repacked and good to flash

seanzscreams said:
Lastly the rundown is like this
if you want to take a ota blob
and extract the contents for a raw base
and a raw kernel
1
take the ota and extract the blob file and place
in your folder with blobtools
2. then run
Code:
blobunpack.exe blob
Which now creates
Blob.APP =System.img (can be renamed system.img and unyaffed in the kitchen)or straight cygwin
Blob.sos=Recovery Img
Blob.Ebt=Bootloader information
Blob.Lnx=kernel (can also just be renamed boot.img and unyaffed in kitchen)
Blob.pt=Partition info
so to repack lets say your custom remade image
and your custom kernel
and a recovery of your choice
run
Code:
blobpack.exe -s blob lnx boot.img sos twrp.blob app system.img
then simply take the blob replace in the ota file
and flash in recovery
and it should flash a rom packed as a blob
Click to expand...
Click to collapse
Hi!
For a linux (Ubuntu) machine you can easily unpack blob.APP
> sudo mkdir mnt
> sudo mount -o loop blob.APP mnt
- now in your mnt directory , you will have /system ! :good:

Hi,
My TF300tl can't unlock bootloader. so can I use this way to pack custom ROM ( cm11, liplop...) as official ROM to flash for my tablet ?

konnichiwa said:
Hi,
My TF300tl can't unlock bootloader. so can I use this way to pack custom ROM ( cm11, liplop...) as official ROM to flash for my tablet ?
Click to expand...
Click to collapse
I wouldn't think so, as the ROM would have to be signed to be official

[Q] [kitchen][help me!!]cant build a new boot.img

Found BOOT-EXTRACTED folder, checking contents ...
Found boot.img-ramdisk
Found zImage
Working folder found
od: boot.img: No such file or directory
Compiling mkbootfs ...
Error: mkbootfs not successfully compiled!
Press Enter to continue
how to solve it ??

push

[Q] Help Compiling kernel from sony source

[email protected]:/home/anikesh/android/kernel# make -j8
CHK include/linux/version.h
CHK include/generated/utsrelease.h
CC scripts/mod/empty.o
make[1]: `include/generated/mach-types.h' is up to date.
CC kernel/bounds.s
/root/home/anikesh/android/android_prebuilt_toolchains/arm-eabi-4.4.3/bin/arm-eabi-gcc: No such file or directory
Is your PATH set correctly?
make[2]: *** [scripts/mod/empty.o] Error 2
make[1]: *** [scripts/mod] Error 2
make: *** [scripts] Error 2
make: *** Waiting for unfinished jobs....
/root/home/anikesh/android/android_prebuilt_toolchains/arm-eabi-4.4.3/bin/arm-eabi-gcc: No such file or directory
Is your PATH set correctly?
make[1]: *** [kernel/bounds.s] Error 2
make: *** [prepare0] Error 2
[email protected]:/home/anikesh/android/kernel#
Pls Can someone Help?

Do you have the prebuilt toolchains installed
And if so, do you have them placed in /android/android_prebuilt_toolchains?
Sent from my LT26i using XDA Premium 4 mobile app

Envious_Data said:
Do you have the prebuilt toolchains installed
And if so, do you have them placed in /android/android_prebuilt_toolchains?
Sent from my LT26i using XDA Premium 4 mobile app
Click to expand...
Click to collapse
i have solved that problem. thanks btw.
i m using this guide
http://forum.xda-developers.com/showthread.php?t=2285731
now i have created kernel.elf file and when i flash it to my device xperia S i just get a black screen that turns on for 5 sec and den off continuously. i haven't changed any configuration and no changes in ramdisk... simply just compiled with no errors .. then why the kernel is not booting.. Am i doing some thing wrong?

anikesh102 said:
i have solved that problem. thanks btw.
i m using this guide
http://forum.xda-developers.com/showthread.php?t=2285731
now i have created kernel.elf file and when i flash it to my device xperia S i just get a black screen that turns on for 5 sec and den off continuously. i haven't changed any configuration and no changes in ramdisk... simply just compiled with no errors .. then why the kernel is not booting.. Am i doing some thing wrong?
Click to expand...
Click to collapse
Did you implement all the makefile and defconfig fixes for making the toolchain work....you can find it in xda..search doomlords tutorial for compiling xperia kernels...link is also in my tool thread in the faq section....link is in my signature

Dark Wraith said:
Did you implement all the makefile and defconfig fixes for making the toolchain work....you can find it in xda..search doomlords tutorial for compiling xperia kernels...link is also in my tool thread in the faq section....link is in my signature
Click to expand...
Click to collapse
yes i saw your thread.. and yes i made those changes.. i want to build the kernel without modifying anything... i ll tell u what i did..
1. extracted source
2. changed the directory
3. export ARCH=arm
4. export CROSS_COMPILE=~/arm-linux-androideabi-4.7/bin/arm-linux-androideabi-
5. make fuji_nozomi_defconfig
6. make menuconfig (didn't do any changes)
7. edited makefile with Doomlord's fix
8. edited .config with Doomlord's fix
9. make -j5
it successfully compiled with no errors
now the i got the zImage
then i made a folder "compile" which consist of RPM.bin, mkelf.py, zImage, ramdisk.img
here RPM.bin and ramdisk.img are extracted from kernel.sin from official ftf file and mkelf.py from Doomlord's
10. python mkelf.py -o kernel.elf [email protected] [email protected],ramdisk [email protected],rpm
that's all i got kernel.elf and flashed it to my device.
So now pls tell me have i done something wrong?

anikesh102 said:
yes i saw your thread.. and yes i made those changes.. i want to build the kernel without modifying anything... i ll tell u what i did..
1. extracted source
2. changed the directory
3. export ARCH=arm
4. export CROSS_COMPILE=~/arm-linux-androideabi-4.7/bin/arm-linux-androideabi-
5. make fuji_nozomi_defconfig
6. make menuconfig (didn't do any changes)
7. edited makefile with Doomlord's fix
8. edited .config with Doomlord's fix
9. make -j5
it successfully compiled with no errors
now the i got the zImage
then i made a folder "compile" which consist of RPM.bin, mkelf.py, zImage, ramdisk.img
here RPM.bin and ramdisk.img are extracted from kernel.sin from official ftf file and mkelf.py from Doomlord's
10. python mkelf.py -o kernel.elf [email protected] [email protected],ramdisk [email protected],rpm
that's all i got kernel.elf and flashed it to my device.
So now pls tell me have i done something wrong?
Click to expand...
Click to collapse
try python mkelf.py -o kernel.elf [email protected] [email protected],ramdisk [email protected],rpm
and tell the result....before doing it....go to the kernel folder and do a make clean

Dark Wraith said:
try python mkelf.py -o kernel.elf [email protected] [email protected],ramdisk [email protected],rpm
and tell the result....before doing it....go to the kernel folder and do a make clean
Click to expand...
Click to collapse
yeah i tried that also... result is same.. just a black screen... can u give me a complete procedure like i told u what i did... or pls just tell me how to create kernel.elf...
from where to get all these files -
ramdisk.cpio.gz
RPM.bin
mkelf.py
i extracted kernel.elf.rpm.bin and kernel.elf.ramdisk.gz from stock kernel.elf(extracted from ftf)
and this kernel.elf.ramdisk.gz(1) file contains kernel.elf.ramdisk(2)
so while using python command i have to use (1) or (2)...
pls help me i m stuck here since last 4 days.

anikesh102 said:
yeah i tried that also... result is same.. just a black screen... can u give me a complete procedure like i told u what i did... or pls just tell me how to create kernel.elf...
from where to get all these files -
ramdisk.cpio.gz
RPM.bin
mkelf.py
i extracted kernel.elf.rpm.bin and kernel.elf.ramdisk.gz from stock kernel.elf(extracted from ftf)
and this kernel.elf.ramdisk.gz(1) file contains kernel.elf.ramdisk(2)
so while using python command i have to use (1) or (2)...
pls help me i m stuck here since last 4 days.
Click to expand...
Click to collapse
normally i do this...extract kernel.sin from ftf package
convert kernel.sin to kernel.elf to get the bin file
unpack kernel.sin to get ramdisk.cpio.gz
now compile the zImage(same way as you did)
use mkelf.py to create kernel.elf...
and no need to flash it to check your kernel.elf...use : fastboot boot kernel.elf...
if you wanna know how to extract kernel.sin...just search...i have forgotten the link..doomlord had created a unpack-kernel.sin.pl file....
or you can use my tool...link is in my signature(Dont mean to promote it..but it has kernel.sin unpacker option.)

Dark Wraith said:
normally i do this...extract kernel.sin from ftf package
convert kernel.sin to kernel.elf to get the bin file
unpack kernel.sin to get ramdisk.cpio.gz
now compile the zImage(same way as you did)
use mkelf.py to create kernel.elf...
and no need to flash it to check your kernel.elf...use : fastboot boot kernel.elf...
if you wanna know how to extract kernel.sin...just search...i have forgotten the link..doomlord had created a unpack-kernel.sin.pl file....
or you can use my tool...link is in my signature(Dont mean to promote it..but it has kernel.sin unpacker option.)
Click to expand...
Click to collapse
That helps me too
Usualy i use rpm_bins and other files from other kernels but now i can make my own entirely from scratch
(usualy i change the recovery for twrp and the boot screen, also usualy edit init so i dont have dual recovery (usualy from ffl kernel)
Sent from my LT26i using XDA Premium 4 mobile app

Envious_Data said:
That helps me too
Usualy i use rpm_bins and other files from other kernels but now i can make my own entirely from scratch
(usualy i change the recovery for twrp and the boot screen, also usualy edit init so i dont have dual recovery (usualy from ffl kernel)
Sent from my LT26i using XDA Premium 4 mobile app
Click to expand...
Click to collapse
I have tried almost all methods of extracting kernel.elf provided in xda... and still i get black screen and the phone doesnt boot up...
so pls tell after extracting kernel.sin from ftf with 7zip what method you use to convert kernel.sin to kernel .elf and how to extract kernel.elf to get all the other files....
i cant even make the phone boot up without making any changes in kernel.. how the hell i m going to make it work wen i make some changes

anikesh102 said:
I have tried almost all methods of extracting kernel.elf provided in xda... and still i get black screen and the phone doesnt boot up...
so pls tell after extracting kernel.sin from ftf with 7zip what method you use to convert kernel.sin to kernel .elf and how to extract kernel.elf to get all the other files....
i cant even make the phone boot up without making any changes in kernel.. how the hell i m going to make it work wen i make some changes
Click to expand...
Click to collapse
One question..are you on a 64 bit machine or 32

Dark Wraith said:
One question..are you on a 64 bit machine or 32
Click to expand...
Click to collapse
i am on 64 bit machine...
since i failed thousands of times i tried to create kernel.elf with all stock files...
so what i did was
extracted kernel.sin with flashtool and got kernel.elf.ramdisk.gz kernel.elf.Image kernel.elf.rpm.bin
and using mkelf.py i made kernel.elf by using this command
python mkelf.py -o kernel.elf [email protected] [email protected],ramdisk [email protected],rpm
this time phone booted up successfully
so now i tried same with zImage that i compiled and it again failed... with same black screen result.
so i think the problem is with the zImage that i compiled.
i m using gcc 4.7 toolchain... and made necessary fixes in makefile and .config file..(by DoomLord's) but still failed
i was getting warning like -
arm-eabi-ld: warning: unwinding may not work because EXIDX input section 61 of arch/arm/mach-msm/built-in.o is not in EXIDX output section
for vmlinux , vmlinux1, vmlinux2 file while make
so i changed
CONFIG_ARM_UNWIND=y
to
CONFIG_ARM_UNWIND=n
in .config file
just to be sure the default config file is .config in kernel folder?
and for zImage i do
1. extracted source
2. changed the directory
3. export ARCH=arm
4. export CROSS_COMPILE=~/arm-linux-androideabi-4.7/bin/arm-linux-androideabi-
5. make fuji_nozomi_defconfig
6. make menuconfig (didn't do any changes)
7. edited makefile with Doomlord's fix
8. edited .config with Doomlord's fix
9. make -j5
is this right?

anikesh102 said:
i am on 64 bit machine...
since i failed thousands of times i tried to create kernel.elf with all stock files...
so what i did was
extracted kernel.sin with flashtool and got kernel.elf.ramdisk.gz kernel.elf.Image kernel.elf.rpm.bin
and using mkelf.py i made kernel.elf by using this command
python mkelf.py -o kernel.elf [email protected] [email protected],ramdisk [email protected],rpm
this time phone booted up successfully
so now i tried same with zImage that i compiled and it again failed... with same black screen result.
so i think the problem is with the zImage that i compiled.
i m using gcc 4.7 toolchain... and made necessary fixes in makefile and .config file..(by DoomLord's) but still failed
i was getting warning like -
arm-eabi-ld: warning: unwinding may not work because EXIDX input section 61 of arch/arm/mach-msm/built-in.o is not in EXIDX output section
for vmlinux , vmlinux1, vmlinux2 file while make
so i changed
CONFIG_ARM_UNWIND=y
to
CONFIG_ARM_UNWIND=n
in .config file
just to be sure the default config file is .config in kernel folder?
and for zImage i do
1. extracted source
2. changed the directory
3. export ARCH=arm
4. export CROSS_COMPILE=~/arm-linux-androideabi-4.7/bin/arm-linux-androideabi-
5. make fuji_nozomi_defconfig
6. make menuconfig (didn't do any changes)
7. edited makefile with Doomlord's fix
8. edited .config with Doomlord's fix
9. make -j5
is this right?
Click to expand...
Click to collapse
Did you download the additional libraries required for a 64 bit machine?

Dark Wraith said:
Did you download the additional libraries required for a 64 bit machine?
Click to expand...
Click to collapse
i downloaded many of them but i don't remember.
which ones r u talking about?

anikesh102 said:
i downloaded many of them but i don't remember.
which ones r u talking about?
Click to expand...
Click to collapse
Gimme a moment
This one:
g++-multilib gcc-multilib lib32ncurses5-dev lib32readline-gplv2-dev lib32z1-dev

Dark Wraith said:
Gimme a moment
This one:
g++-multilib gcc-multilib lib32ncurses5-dev lib32readline-gplv2-dev lib32z1-dev
Click to expand...
Click to collapse
ohhkk i installed this just now.. i think i installed some of them before..
anyways i will compile again and tell the result..
is my process correct? and .config is the defconfig file?

anikesh102 said:
ohhkk i installed this just now.. i think i installed some of them before..
anyways i will compile again and tell the result..
is my process correct? and .config is the defconfig file?
Click to expand...
Click to collapse
yes........to be honest...even i had this problem the first time but i dont remember how i resolved it...
i think its library problem...64 bit machines need these libraries extra...lets see..lemme know how it goes...

Dark Wraith said:
yes........to be honest...even i had this problem the first time but i dont remember how i resolved it...
i think its library problem...64 bit machines need these libraries extra...lets see..lemme know how it goes...
Click to expand...
Click to collapse
i always get this problem...
so when i change
CONFIG_ARM_UNWIND=y
to
CONFIG_ARM_UNWIND=n
in .config file
den no warning occurs.. so should i do that?

is this output right?

That doesnt look right even to me
Something may not be right with the makefile
Warnings are better at this point... Its just warnings, usualy i use a different GCC or ignore them
What do you think @Dark Wraith
Sent from my LT26i using XDA Premium 4 mobile app

[BOOT IMAGE] Stock boot with su.d & init.d support | 20.05.2016

As the title states this is a stock boot.img with init.d support.
Download >>> https://mega.nz/#!Nwx0BD5T!TZB0ngp3spi3myFAFw7gtx0z8zu7O2BRLv2UC2HTJ4M
XDA:DevDB Information
[BOOT IMAGE] Stock boot with su.d & init.d support, Kernel for the Elephone P9000
Contributors
Jonny
Kernel Special Features:
Version Information
Status: Stable
Stable Release Date: 2016-05-20
Created 2016-05-18
Last Updated 2016-05-20

this cant work . sry

skeleton1911 said:
this cant work . sry
Click to expand...
Click to collapse
Should do, same way I used to fire init.d on other devices (M9). Of course with SuperSU installed init.d is kind of deprecated as su.d is a better solution.

Jonny said:
Should do, same way I used to fire init.d on other devices (M9). Of course with SuperSU installed init.d is kind of deprecated as su.d is a better solution.
Click to expand...
Click to collapse
no sorry i dont work.
look:
in init.rc you wrote that
Code:
service sysinit /system/xbin/busybox run-parts /system/etc/init.d
class main
oneshot
user root
group root
that is going to sysinit . but sysinit service is not present in in system, check it yourself
if you would use this . it would work at boot
Code:
service[COLOR="Red"] userinit[/COLOR] /system/xbin/busybox run-parts /system/etc/init.d
oneshot
class late_start
user root
group root
and users have to install busybox and add the init.d folder into system/etc manual
set permissions to 755 or 777 for the init,d folder and the scripts they want to use

Ah cheers, I forgot to add the sysinit binary. Tbh though I think I'm going to look more into su.d as it seems more reliable in where in the boot process it executes the script :good:

Link updated. New zip flashes and installs busybox and creates the su.d and init.d folders with correct permissions. This one now supports both init.d and su.d (recommended).

Jonny said:
Link updated. New zip flashes and installs busybox and creates the su.d and init.d folders with correct permissions. This one now supports both init.d and su.d (recommended).
Click to expand...
Click to collapse
now it works . great job

Jonny said:
As the title states this is a stock boot.img with init.d support.
Click to expand...
Click to collapse
What tools did you use to repack the kernel and ramdisk ? I've used nearly ten tools with a non working boot image after modifying default.prop only.
Please advise about any tricks to do that.
Thanks.

nmset said:
What tools did you use to repack the kernel and ramdisk ? I've used nearly ten tools with a non working boot image after modifying default.prop only.
Please advise about any tricks to do that.
Thanks.
Click to expand...
Click to collapse
What did you edit in the boot image?
Sent from my Elephone P9000 using XDA Labs

Jonny said:
What did you edit in the boot image?
Click to expand...
Click to collapse
I unpacked the boot image, then the ramdisk, edited default .prop changing ro.adb.secure from 1 to 0.
Repacked the ramdisk with
find . | cpio --owner root:root -ov -H newc | gzip -9 > ../ramdisk.cpio.gz
After repacking the boot image with many tools, no way to get a working one.

nmset said:
I unpacked the boot image, then the ramdisk, edited default .prop changing ro.adb.secure from 1 to 0.
Repacked the ramdisk with
find . | cpio --owner root:root -ov -H newc | gzip -9 > ../ramdisk.cpio.gz
After repacking the boot image with many tools, no way to get a working one.
Click to expand...
Click to collapse
It's editing that line, I've tried it previously myself and it just ends up with a boot image that doesn't work.
Sent from my Elephone P9000 using XDA Labs

Jonny said:
It's editing that line, I've tried it previously myself and it just ends up with a boot image that doesn't work.
Click to expand...
Click to collapse
If I just unpack the original boot image and the ramdisk, and repack everything without any modifications, the resulting boot image is not functional.
If I unpack the original boot image, and do not unpack the ramdisk, then repack the kernel and ramdisk, the resulting boot image works perfectly.
It seems related with the ramdisk format, or its header, or addresses and offsets, or whatever, I wish you could share how you got a working boot image.
Thanks.

nmset said:
If I just unpack the original boot image and the ramdisk, and repack everything without any modifications, the resulting boot image is not functional.
If I unpack the original boot image, and do not unpack the ramdisk, then repack the kernel and ramdisk, the resulting boot image works perfectly.
It seems related with the ramdisk format, or its header, or addresses and offsets, or whatever, I wish you could share how you got a working boot image.
Thanks.
Click to expand...
Click to collapse
I use Android Image Kitchen, but I've still had the same results as you when editing that line

Jonny said:
I use Android Image Kitchen, but I've still had the same results as you when editing that line
Click to expand...
Click to collapse
Code:
find . | cpio -o -a --reproducible -R 0:0 -H newc | gzip -9 > ../ramdisk.cpio.gz
That did the trick.
(As a sidenote, I did not have the expected result, i.e, a root shell with 'adb shell', after 'adb root', one more paranoid regression from Google.)
:crying:

nmset said:
Code:
find . | cpio -o -a --reproducible -R 0:0 -H newc | gzip -9 > ../ramdisk.cpio.gz
That did the trick.
(As a sidenote, I did not have the expected result, i.e, a root shell with 'adb shell', after 'adb root', one more paranoid regression from Google.)
:crying:
Click to expand...
Click to collapse
For a root shell type 'adb shell' the just type 'su' and accept the superuser prompt on your device.
Adb root is needed for doing the adb remount command to push and pull certain files to /system

booting custom kernel

SOLVED: I was using the G980F boot.img instead of G985F image. THANKS everyone
The device won't reboot if I unpack and repack the boot.img on S20
Did someone else here succeed in flashing a new boot.img ? THANKS
Code:
[email protected]:~/GS20_kernel_build$ unpackbootimg -i boot.img
BOARD_KERNEL_CMDLINE androidboot.hardware=exynos990
BOARD_KERNEL_BASE 10000000
BOARD_PAGE_SIZE 2048
[email protected]:~/GS20_kernel_build$ mkbootimg --kernel boot.img-zImage --ramdisk boot.img-ramdisk.gz -o boot_repacked.img
[email protected]:~/GS20_kernel_build$ heimdall flash --BOOT ./boot_repacked.img
[...]
Downloading device's PIT file...
PIT file download successful.
Uploading BOOT
100%
BOOT upload successful
Ending session...
Rebooting device...

modem__ said:
The device won't reboot if I unpack and repack the boot.img on S20
Did someone else here succeed in flashing a new boot.img ? THANKS
Code:
[email protected]:~/GS20_kernel_build$ unpackbootimg -i boot.img
BOARD_KERNEL_CMDLINE androidboot.hardware=exynos990
BOARD_KERNEL_BASE 10000000
BOARD_PAGE_SIZE 2048
[email protected]:~/GS20_kernel_build$ mkbootimg --kernel boot.img-zImage --ramdisk boot.img-ramdisk.gz -o boot_repacked.img
[email protected]:~/GS20_kernel_build$ heimdall flash --BOOT ./boot_repacked.img
[...]
Downloading device's PIT file...
PIT file download successful.
Uploading BOOT
100%
BOOT upload successful
Ending session...
Rebooting device...
Click to expand...
Click to collapse
You need to make a tar file containing the img and flash it with odin. You need a Windows computer for that. Linux won't do sadly

If you don't feel like making a flashable zip file you can just use dd to install it from within TWRP (via terminal on console or ADB) if you have that installed:
dd if=boot_repacked.img of=/dev/block/by-name/boot
No Windows/Odin required.

sjevtic said:
If you don't feel like making a flashable zip file you can just use dd to install it from within TWRP (via terminal on console or ADB) if you have that installed:
dd if=boot_repacked.img of=/dev/block/by-name/boot
No Windows/Odin required.
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dd always scares me lol.
You sure this works with S20? Even Fastboot fllashing doesn't work so I doubt this will

JanBoyGamer23 said:
dd always scares me lol.
You sure this works with S20? Even Fastboot fllashing doesn't work so I doubt this will
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My phone wouldn't boot last night after I tried flashing my own boot image and this was how I put the previous one back. It booted right up.