Power Maix M1w or Bit at 3.3v?

Is it possible to bypass the 5v to 3.3v regulator and power the M1w or the Bit directly from the 3.3v pin?

you can directly connect your 3.3V power source to module’s 5V pins, it will work.
only things changed is 3.3V pins are lower than 3.3V