Google GSI: Generic System Images for Smartphones

After building my own ROM i got some problems with the devices drivers for the modem (the dual SIM was not recognized).

I discussed that with a few very skilled Android developers and the device drivers are the most important problem for building ROMs.

But there is something called GSI: Generic System Images.

(s. https://source.android.com/setup/build/gsi)

and:

The good point is that for my Samsung J530 there was a developer which built a project which allows to install GSIs:

https://forum.xda-developers.com/galaxy-j7-2017/development/treble-projecttreble-v1-0-jxy17lte-t3929286

With this plus Havoc 3.5

https://forum.xda-developers.com/galaxy-j7-2017/development/rom-crdroid-6-3-android-q-10-0-galaxy-t4048917

And here the steps to Android 10 (which where provided to me by Micro[ice]:

1. install TWRP 3.3.0
   
2. install create vendor 2.0
3. reboot recovery
4. install project spaget x
   (if u get symlink error 7 flash revert vendor 2.0 and repeat from step 1 without revert vendor 2.0)
5. install GSI (Havoc)-OS to system partition
   (dont reboot after u flash project spaget x)
6. if u need to flash gapps first u need to go
   Wipe -> Advanced Wipe -> Tick System -> Repair -> Resize
   (if u get error 1 resize again it will be successful) then u flash gapps
7. (optional) flash areskernel rc2
8. (optional) flash magisk
9. reboot
10. enjoy

And after that i have a running Android 10 on my Samsung J5... (without any Samsung Bloatware)

Lineage OS: Building my own system from scratch...

For my Samsung J5 is was only able to find a lineage 15.1 image but no lineage 16 or even 17.
So i decided to build the image on my own.

I followed this guide:
https://github.com/lineage-doge/device-j5y17lte/tree/lineage-16.0

But on this page the roomservice.xml is wrong:

Just change it to

The rest was following the instructions:

mkdir -p android/lineage-16.0
cd android/lineage-16.0
repo init -u git://github.com/LineageOS/android.git -b lineage-16.0
repo sync

Create .repo/local_manifests/roomservice.xml with the content shown above.
Then run "repo sync" once again.

Most important point it to extract the binaries from your device. To get a background just read this:
https://wiki.lineageos.org/extracting_blobs_from_zips.html


I extracted /system from my Android device via TWRP (under advanced you can find a file explorer and this can copy the partition to your sd card).
After that point STOCK_ROM_DIR to your sd card and run:

cd device/samsung/j5y17lte
STOCK_ROM_DIR=/path/to/system ./extract-files.sh

Now we are ready to rumble:

cd ../../
source build/envsetup.sh
brunch lineage_j5y17lte-userdebug

But after some minutes:

LD      kernel/built-in.o
/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/kernel/samsung/exynos7870/drivers/net/wireless/Makefile:62: android version 1: 90000
/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/kernel/samsung/exynos7870/drivers/net/wireless/Makefile:63: MAJOR_VERSION version 1: 9
/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/kernel/samsung/exynos7870/drivers/net/wireless/Makefile:107: platform version 3 : 9.0.0
/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/kernel/samsung/exynos7870/drivers/net/wireless/Makefile:108: MAJOR_VERSION version 3: 9
  LD      drivers/built-in.o
make[1]: Leaving directory '/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/out/target/product/j5y17lte/obj/KERNEL_OBJ'
Makefile:145: recipe for target 'sub-make' failed
make: *** [sub-make] Error 2
make: Leaving directory '/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/kernel/samsung/exynos7870'
[  1% 555/35382] target StaticLib: libv8src_32 (/media/schroff/895337b7-c4eb-44a4-...arget/product/j5y17lte/obj_arm/STATIC_LIBRARIES/libv8src_intermediates/libv8src.a)
ninja: build stopped: subcommand failed.
19:21:20 ninja failed with: exit status 1

#### failed to build some targets (05:29 (mm:ss)) ####

But this error is easy to fix:

cd ~/android/lineage-16.0/out/target/product/j5y17lte/obj/KERNEL_OBJ/firmware/tsp_imagis
cp ~/android/lineage-16.0/kernel/samsung/exynos7870/firmware/tsp_imagis/ist3038h_a3x_cmcs.bin .
~/android/lineage-16.0/kernel/samsung/exynos7870/firmware/tsp_imagis/ist3038h_a3x.fw .
schroff@zerberus:~/android/lineage-16.0/out/target/product/j5y17lte/obj/KERNEL_OBJ/firmware/tsp_imagis$

and try once again!

And after a while:

  Imgdiff Stats Report 
========================

Compressing system.new.dat with brotli
  running:  brotli --quality=6 --output=/tmp/tmpAOkKFk/system.new.dat.br /tmp/tmpAOkKFk/system.new.dat
using prebuilt boot.img from BOOTABLE_IMAGES...
  running:  java -Xmx2048m -Djava.library.path=/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/out/host/linux-x86/lib64 -jar /media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/out/host/linux-x86/framework/signapk.jar -w build/target/product/security/testkey.x509.pem build/target/product/security/testkey.pk8 /tmp/tmptUxdfx.zip /tmp/tmpSgxnBy.zip
  running:  zip -d /tmp/tmpSgxnBy.zip META-INF/com/android/metadata
  running:  java -Xmx2048m -Djava.library.path=/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/out/host/linux-x86/lib64 -jar /media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/out/host/linux-x86/framework/signapk.jar -w build/target/product/security/testkey.x509.pem build/target/product/security/testkey.pk8 /tmp/tmpSgxnBy.zip /media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/out/target/product/j5y17lte/lineage_j5y17lte-ota-eng.schroff.zip
done.
[100% 453/453] build bacon
Package Complete: /media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/lineage-16.0/out/target/product/j5y17lte/lineage-16.0-20200502-UNOFFICIAL-j5y17lte.zip

#### build completed successfully (27:31 (mm:ss)) ####

Custom ROMs: Installing via TWRP (e.g. Prometheus ROM)

After installing TWRP and installing some ROMs via adb sideload, (or this story with my old Nexus 7) i learned that there is another way for installing Custom ROMs:

• Boot in to recovery (Samsung: Home Button + Power + Volume Up)
• Copy the ROM.zip to the SD card of the smartphone
• and then follow this screenshots

Click on "Install"

Click "Select Storage"

Select your SD card

Select the ROM you want to install:

Swipe to the right

Then some of the ROMs (like Prometheus) will guide you through an installation wizard, where you can chose some options.

If you want to try Prometheus you can download it here.

Building my own Recovery ROM for a Samsung J5 2017 (j5y17lte, TWRP)

After several hours of sideloading a custom ROM and flashing a TWRP recovery image i thought the next step is to build a TWRP recovery image on my own.

What is a TWRP recovery image?

So how to do that?

My startpoint was

https://github.com/Doge-Jxy17lte/twrp-jxy17lte

(just search github for your device with TWRP)

But this is not the way to begin.

First you have to follow this page:

https://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni

and do

repo init -u git://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni.git -b twrp-7.1

and

repo sync

Then add the j5y17lte.xml to .repo/local_manifests. After that the repo sync works but the

$ lunch omni_j5y17lte-eng

ends up with a warning:

WARNING: device/samsung/j5y17lte/omni.dependencies file not found

============================================

PLATFORM_VERSION_CODENAME=REL

PLATFORM_VERSION=7.1.2

TARGET_PRODUCT=omni_j5y17lte

TARGET_BUILD_VARIANT=eng

TARGET_BUILD_TYPE=release

TARGET_BUILD_APPS=

TARGET_ARCH=arm64

TARGET_ARCH_VARIANT=armv8-a

TARGET_CPU_VARIANT=cortex-a53

TARGET_2ND_ARCH=arm

TARGET_2ND_ARCH_VARIANT=armv7-a-neon

TARGET_2ND_CPU_VARIANT=cortex-a53

HOST_ARCH=x86_64

HOST_2ND_ARCH=x86

HOST_OS=linux

HOST_OS_EXTRA=Linux-4.15.0-88-generic-x86_64-with-Ubuntu-18.04-bionic

HOST_CROSS_OS=windows

HOST_CROSS_ARCH=x86

HOST_CROSS_2ND_ARCH=x86_64

HOST_BUILD_TYPE=release

BUILD_ID=NJH47F

OUT_DIR=/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/omni/out

============================================

The good point: just ignore this warning and do the mka recoveryimage.

Here i got two errors:

/bin/bash -c "prebuilts/misc/linux-x86/flex/flex-2.5.39 -oout/target/product/generic/obj/STATIC_LIBRARIES/libedify_intermediates/lexer.cpp bootable/recovery/edify/lexer.ll"
flex-2.5.39: loadlocale.c:130: _nl_intern_locale_data: Assertion `cnt < (sizeof (_nl_value_type_LC_TIME) / sizeof (_nl_value_type_LC_TIME[0]))' failed.
Aborted (core dumped)

Here i followed this hint:
https://groups.google.com/forum/?hl=tr#!topic/android-building/0kzPnw3akxg
and copied the provided flex to "prebuilts/misc/linux-x86"
   cp ~/Downloads/build/flex flex-2.5.39

You have to change the name from flex to flex-2.5.39 and you have to rerun source build/envsetup.sh again.

Then i got the following errors:

bootable/recovery/gui/../twrp-functions.hpp:24:10: fatal error: 'ext4_utils/ext4_crypt.h' file not found

bootable/recovery/gui/../twrp-functions.hpp:24:10: error: 'ext4_utils/ext4_crypt.h' file not found with <angled> include; use "quotes" instead

bootable/recovery/twrp.cpp:49:10: fatal error: 'base/strings.h' file not found

This i could resolve with:

cd bootable/recovery

ln -s ../../system/extras/ext4_utils

vi twrp-functions.hpp # add the quotes!

ln -s ../../system/core/base/include/android-base base

After that the build went through and i got a TWRP image:

-rw-rw-r--  1 schroff schroff 26937344 Mai 17 23:40 recovery.img

This ran without a problem on my J5 after a

heimdall flash --RECOVERY recovery.img