"The upper left corner, next to the signal display" is the operator's signal icon, which needs to be jailbroken to modify.
There are many plug-ins that can modify the operator icon after jailbreaking, such as zeppelin and 360. The following uses Zeppelin as an example to introduce how to use it: (the same applies to other software)
Zeppelin is a A very powerful operator logo customization modification plug-in, with multiple sets of exquisite patterns built-in and the function of importing and replacing user-made logos.
Installation and usage instructions:
Step one: After jailbreaking, search and install Zeppelin in Cydia (if you cannot find it, please search the Zeppelin source on Baidu yourself, add the source and search again to download).
Step 2: If you want to replace the carrier text, enter the system settings - Zeppelin, click on the Carrier Text in the upper right corner to modify and replace it.
Step 3: You can also replace various operator icons, click Theme to enter the selection (some icons are built into the plug-in), and it will take effect immediately; you can also make your own or search the Zeppelin icon file in the forum and import it into the /Library/Zeppelin directory Next, then go back to System Settings - Zeppelin to make a selection.