Another alternative that AI has given me, I've passed it on to my colleague and am waiting for his response, in case you want to try it.
-ERROR MESSAGE-
The package in the root directory of the USB flash drive is not recognized correctly. Please check if the storage address of the package is correct.
This error is very specific: the system is looking for the control file in the wrong place or in a format it doesn't like. On the MG4, when this exact message appears, it's usually for one of these three reasons:
-1. The "double" installer.json (Master Trick)
The R30 system sometimes has a routing bug. To fix it, do this on your USB drive:
Copy the installer.json file to the root directory.
Copy the same installer.json file AGAIN into the AVN_MPU folder (next to update.zip).
This way, the car will find it no matter what, regardless of the route it's mapping internally.
-2. The USB "GPT" vs. "MBR" Problem
This is the most common technical error in 2024 models. If your USB drive was prepared on a modern computer, it likely uses a GPT partition table, but the car only understands MBR.
How to fix it: You need to format the USB drive using a free tool like Rufus.
In Rufus, select: Partition scheme: MBR and Target system: BIOS or UEFI.
Format: FAT32.
If the USB drive is GPT, the car will see the folders, but the low-level installer (the one that throws the error) won't be able to read the file.
-3. File Name Cleanup (Hidden Extensions)
Make sure Windows isn't misleading you with file extensions:
If you see the file as update.zip.zip or installer.json.txt (because Windows hides known extensions), the car will throw an error.
Verification: Right-click on the file -> Properties. Make sure the "File type" is exactly .json and .zip.
Your final structure should look like this: "Duplicate the .json file in both locations"
USB:\installer.json
USB:\AVN_MPU\installer.json (Extra copy)
USB:\AVN_MPU\update.zip