I think that boards attached to the Gumstix expansion boards cannot run with voltages less than 4V.
At least that's what the Gumstix website says. I think that's because of some voltage regulators on the board.

Hi I have a system (Earth and expansion board) which works fine with the external power supply. I have now removed the expansion board and have connected the Earth board to a 3.7V battery, but the system donít boot from the SD card now. Do I need do something additional to start the power up sequence ? Best Regards Rytter

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