I have 2 430 EX's, and ST- E3-RT transmitter. All i use is the radio slave mode, firing with the transmitter. Frustrating, sometimes when i change batteries i guess, or out of the blue i can not access radio slave. It defaults to ETTL, i switch to M, WIRELESS OFF is displayed. I enter that menu, scroll and press radio SLAVE and it bumps me back to ETTL. I have them all in different groups, and this time both flashes are doing the same thing. It seems when i changed modes on the transmitter it balled things up. Any help much appreciated.