When issuing GDB `continue` in RAM, can I write to the adresses from which I `continue`d?
I'm resetting the development board with the reset button


Don't do that while OpenOCD is running. Use OpenOCDs reset halt or reset run commands instead. 

The reset button will affect the internal debugging state of the target but OpenOCD may not detect that correctly, depending which debugger you use and how it is wired up.

Note that you should do reset init before you load the binary to flash.