unknownbaka / msm8953_offset_voltage

test on redmi note 4x

cpu voltage offset on msm8953

The shell script use for msm8953(Snapdragon 625) undervolt

#include <std_disclaimer.h>

/*
 * Your warranty is now void.
 *
 * We are not responsible for bricked devices, dead SD cards,
 * thermonuclear war or you getting fired because the alarm app failed. Please
 * do some research if you have any concerns about features included in this ROM
 * before flashing it! YOU are choosing to make these modifications and if
 * you point the finger at us for messing up your device, we will laugh at you. Hard & a lot.
 *
 */

prebuilt tools

There are 3 prebuilt tools in prebuilt/.

1. magiskboot used to pack/unpack boot.img.
2. dtp used to split kernel_dtb into sub kernel_dtb-*.(one kernel_dtb exract from boot.img contains some dtbs, only one dtb is vaild)
3. dtc used to decompile dtb file to dts file.

processes

1. use dd command to get boot.img
2. use magiskboot to unpack boot.img into kernel+kernel_dtb
3. use dtp to split kernel_dtb into sub kernel_dtb-*
4. find the adapted dtb according to qcom, board-id and qcom, msm-id, and then use dtc to decompile the selected dtb(binary) into .dts(source)
5. Modify screen refresh rate by change qcom,mdss-dsi-panel-framerate qcom,mdss-dsi-max-refresh-rate in device-tree source file
6. undervolt by change qcom,cpr-open-loop-voltage-fuse-adjustment qcom,cpr-closed-loop-voltage-fuse-adjustment qcom,cpr-closed-loop-voltage-adjustment in device-tree source file
7. compile dts to dtb and pack boot.img

prepare

1. Termux: Google Play(or other)
2. Your device is rooted

usage

./dtb_process.sh -i -c -f [-u undervolt] [-b overvolt] [-s screen refresh rate] 
    -i              install boot.img after generation
    -c              does not cleanup workspace after finished(you wanna debug)
    -f              force backup the current boot(milestone) to /sdcard/Android/, otherwise only backup boot on first time
    -u              cpu undervolt value, default 0, range(0-125), unit mv
    -b              cpu overvolt value, default 0, range(0-125), unit mv
    -s              screen refresh rate value, default unchanged, unit hz

Let's go

get the srcipt

open termux bash and get script:

$ su
:/data/data/com.termux/files/home # curl https://github.com/unknownbaka/msm8953_offset_voltage/blob/msm8953/dtb_process.sh > dtb_process.sh

undervolt!! if not set -u and -g, default undervolt cpu 100mv(default 0 mv)

:/data/data/com.termux/files/home # sh dtb_process.sh -u 100

install the new boot

:/data/data/com.termux/files/home # dd if=./new-boot.img of=/dev/block/bootdevice/by-name/boot

or use option -i(then you don't need step install the new boot)

:/data/data/com.termux/files/home # ./dtb_process.sh -u 100 -i

same as overvolt please remember set -u and -b 0, because (no longer need) the final offset=(-b value)-(-u value)

:/data/data/com.termux/files/home # ./dtb_process.sh -b 100

if you want to change the screen refresh rate

:/data/data/com.termux/files/home # ./dtb_process.sh -s 90

if you are boring

:/data/data/com.termux/files/home # ./dtb_process.sh -u 90 -b 100    # same as ./dtb_process.sh -b 10

restore

if something goes wrong, you can restore your origin boot, please check /sdcard/Android/ for the original boot image name.

do remember to delete old boot.img after flashed a new ROM, otherwise the script will not backup the new rom boot.

su
dd if=/sdcard/Android/boot-*.img of=/dev/block/bootdevice/by-name/boot  # change it!

special thanks

• asto18089
• 南昌狗头人(coolapk)