Q:

android: Get instant current from NON-supported devices

I saw that several android devices dont support BATTERY_PROPERTY_CURRENT_NOW to get instant current. 
Is there any way to get instant battery current values for these devices? If we root them? 
Is it a hardware limitation on these devices or software limitation?

A:

Most properties are read from kernel power_supply subsystem attributes of similar names. However, the exact properties, resolution of property values, and update frequency available for a specific device depend on:
Fuel gauge hardware, such as a Summit SMB347 or Maxim MAX17050.
Fuel gauge-to-system connection, such as the value of external current sense resistors.
Fuel gauge chip software configuration, such as values chosen for average current computation intervals in the kernel driver.

Official Documentation
Which means yes, it's a hardware/software limitation. It depends

