imx-bootlets does not handle VDD5V or DCDC_BATT only sources very well.
We have created a patch to add the most robust support possible for a VDD5V or DCDC_BATT only configuration.
It implies enabling of hardware mechanisms to automatically shutdown when the one configured
source becomes invalid. The default power_prep.c file normal tries to configure the protection
as if two sources might be present and thus in some cases, tries to make some determination as
to what to do in software upon one of the power sources becoming invalid.
You can get the patch from freescale.com