Playing with the machine and playing with the machine------Advanced and improved Qualcomm engineering line production method.

Many ordinary players' definition of the engineering line is still in the early operation cognition of shorting the red and green ends. For example this

Conventional Production Engineering Line

 

 

 Or short circuit board contacts

 

What I will describe to you today is a more advanced and improved engineering line. Because this kind of engineering line in the early stage has no effect on Mi 6 or other models of the same period. Later models need to dismantle the machine and manually short the motherboard contacts to enter the Qualcomm edl mode. Or a privileged operation to enter edl mode. There are still some difficulties for novices. At present, many maintenance dongles or certain treasures have such engineering lines for sale. The principle is also very simple, but it requires a certain amount of manual operation.

Early engineering line definition and Testpoint mode. However, Android 10 or subsequent higher versions that have been updated to the latest security patch level in August/September 2021 are not verified on a separate Testpoint. Instead, a special method is introduced to detect mobile software and safe areas. This is one of the reasons why the old version of the engineering line does not work

EDL mode is also known as the emergency mode of the mobile phone. Technically, all Xiaomi Redmi devices, or any Qualcomm chip models, have the EDL mode option. If you want to install a rescue brick or update your own Qualcomm phone, then you have a lot of options to use. Recovery mode or use fastboot mode to flash a new stock ROM on the device. These two methods have some limitations, for example, Recovery ROM can only be used to update the higher version, and cannot downgrade the Xiaomi version.

 Tools and accessories required for operation

Data lines
Resistors 10k and 56K ohms
Soldering materials (soldering gun, solder, solder paste, etc.)

Yellow wire indicates CC pin, red wire indicates VBUS
56K resistor between CC2 pin and VBUS
10K resistor between CC1 pin and VBUS

At present, this improved engineering line has passed the test

Some models tested:

Mi 9 Mi
Mi 9 Pro 5G
Mi 10
Mi 10 S
Mi 11 Pro 
Mi 11 Ultra 

Mi 12 Xiaomi
Mi MIX4
Xiaomi Mi CC9 Pro

Redmi K20Redmi
K20 ProRedmi
K30 4GRedmi
K30 5GRedmi
K30 ProRedmi
K40Redmi
Note 9
ProRedmi Note 9

Huawei Honor Magic3Huawei
Honor Magic3 ProHuawei
P50Huawei
P50 ProHuawei
P50 PocketHuawei
NOVA 9Huawei
NOVA 9 ProHuawei
Hi NOVA 9Huawei
Hi NOVA 9 Pro

Wait for some models

Final tip. For starters. There are certain risks. Novices are still advised to buy finished products. This kind of operation is still for friends with strong manual experience and certain hardware knowledge.

If it is helpful to you, can you extend your lovely hands and give it a thumbs up. Follow me to learn about some experience and solutions for playing with machines.