Never heard of such issues before, select should do nothing, except the original game used the select button. Save states should be saved automatically to the internal memory of the Dingoo.
in the last 2 weeks, a new Dingoo revision appeared, that was originally not build for export. Can you provide us with some of the following informations about your Dingoo?
Is it a 2 or 4 GB Model?
Which Firmware is installed? You can check this in the System Setup Menu if you choose About
Each Dingoo has a serial number printed on the left side of the USB port, could you post this number?