(Solved) ICOM A2 show voltage 11.33, unable to program

Several days ago, I send the following email to chinaobd2.com engineer, with BMW ICOM A2 low voltage problem when do programming. This mail content as follows:
When I use BMW ICOM A2 do programming, car engine off or on, shows lower voltage. I have tried with other ISID too, virtual and native on DELL D630.
Reported values by ICOM A2 with engine off 11.3 , with engine on 12.8

I have tested other BMW diagnostics tool, it shows good voltage.
BMW reprogramming requires at least 13V, so I’m unable to do programming, I guess if I use other car for supply voltage to my car, will not be enough too.

Is there a firmware fix or else for this ICOM A2? Is hardware fault?

UOBD2 reply me as follows:
You need to get one additional MST-80 Voltage Regulator Diagnostic Tool, when you use ICOM A2 to program BMW, it will use almost 3 hours or more, show low battery is inevitable, connect to a MST-80 with a Battery Charger and Stability Voltage Equipment to keep ICOM A2 stable voltage. More details about MST-80, you could visit:
https://www.chinaobd2.com/wholesale/mst-80-auto-voltage-regulator-diagnostic-tool.html