Flash the machine - wire brush (only coolpad5891 is used as an example)

Go to the official mobile phone upgrade management page on the computer, download
5891 usb driver.rar
Coolpad CDS self-service upgrade tool V4.27.rar
5891 Resource Pack_2013-07-01_2013.zip
5891 Self-service upgrade package 045 version.zip

Install the driver (after some installations, you need to go to the c drive to install it again in person)

Install the self-service upgrade tool (note: you need to change the computer time to early July 2013 and then restart)

Open the self-service upgrade tool, click directly on the login page to enter, the software takes a long time to open

Connect the phone to the computer (it is very simple when it can be turned on, my phone is bricked, so I can only start it when it is turned off) In case of shutdown, Qualcomm needs to hold down the volume + and power keys to connect to the computer (others only need to connect)

Unzip the 5891 self-service upgrade package version 045.zip 5891 resource package_2013-07-01_2013.zip (you only need to unzip it once)

Change the self-service upgrade program to offline upgrade, select the file you just unzipped (if you do not change the offline upgrade, you need to enter the mobile phone model, hardware number, and mobile phone serial number. I was stuck here for a long time, I can't remember so many numbers T^T)

Then return to the interface to upgrade (need to wait)
After the upgrade is completed, turn on the phone and wait (about ten minutes)
Then congratulations, your phone is no longer a brick\^O^/ (Generally, the phone needs to be wired only after it becomes a brick!)