Ninebot Max ESC Generations
Late in 2021/early 2022, Ninebot released a second version of the G30/Max ESC (Electronic Speed Controller).
Rather than using the well-known STM32 chip most of the previous ESCs were based on, it used an AT32 chip.
This chip is not compatible with currently available CFW (Custom Firmware), though SHFW is currently testing support for it.
It used bullet connectors to connect to the motor.
The second generation of the ESC was more similar to that of the newer generation Xiaomi Mi3 and Mi4 scooters.
It is black plastic and features screw terminals less prone to melting.
It was based on an AT32 chip and incompatible with STM32-based Custom Firmware and STLinking.
How to Identify
Using ScooterHacking Utility v2.1 and above, it's possible to tell which ESC generation you have.
Download the app and connect to your scooter, then click the upper lefthand menu and select "Hardware Details".
Below it will show the MCU that your ESC is based on.
Next to the spot labeled "DRV" is where the chip type is located.
If it says "max_DRV_STM32xxxxxxx" then you have a gen 1 controller and tutorials for STLinking will work.