Ninebot Max Error Code 27
"Master Control Board Password Error, Please replace the Control Board"
Read below if your Ninebot Max G30 or G2 is beeping or has a red wrench icon and flashes this code.
If you clicked the wrong error code, return to the Max G30 and G2 Error Code Index.
Previous Error Code: Ninebot Max Error Code 26 - Next Error Code: Ninebot Max Error Code 28
Cause
Error 27 occurs when rental vehicles are not properly STLinked or an incomplete firmware dump is used.
It can also be caused by using an old serial change method.
This error is the same across the Ninebot SNSC 1.0, SNSC 1.1,ES1, ES2, ES3, ES4, Ninebot G30/Max, G30P, G30D, G30E, and any other Ninebot G30 series scooter.
For ESX, visit Ninebot ESX Error Code 27.
Fix
Temporary
To temporarily fix error 27, hold down the brake and throttle on boot up and release once it beeps.
This also acts as a sort of "lock" mechanism as failure to do this immediately after power-on results in a scooter that will continue beeping until it is turned off, though it is still able to be ridden.
Permanent
Change the serial number twice using a newer dAuth-supported serial change method.
Ninebot IAP, Ninebot-Flasher, and a ScooterHacking Utility all support this.
If that doesn't work, flashing a CFW using max.cfw.sh with error suppression 1 or more enabled will also solve the problem.