Uploading to Seeeduino v2.2 hangs

So I just received a seeeduino v2.2, and plugged it via usb into my computer (Mac OS X 10.5.8). When I plugged it in, the L and TX lights both flashed for a bit, and then only the L light flashed. I tried to upload the Blink sketch, but when I tried, again the TX and L lights blinked, and nothing happened (in the sense that the blinking continued indefinitely while the IDE was "uploading the sketch"). I have tried resetting the board and then uploading, but since the board is in auto reset mode that shouldn't be an issue. I may have accidentally left the board in 3v3 instead of 5v on the first upload attempt, would this have cause a problem with the bootloader? Reading about similar problems it seems that burning the bootloader is always suggested, but I was hoping to avoid it, especially because the guide for doing so on a mac is google translated and so a bit difficult to understand. Is it, however, the only solution?

thanks so much