Beside wireless/bluetooth, is there a way to transfer files from my Osmo Action 1 to an iphone?  I keep getting asked to format the card, which scares me.

otg adapter for iphone and usb/usb c cable

Hi there. Thank you for reaching out and we're sorry for the trouble that this has caused. Since you can only transfer your footage from your DJI Osmo Action to your iPhone via Bluetooth, the other option for transferring the files is via PC using a USB cable.  Please make sure that there is an SD card inserted into the unit also please make sure that you are using a USB Data cable to transmit the data. There must be a pop-up message on the PC when you connect the unit. Hope this helps. Thank you.