Difficult to let my Electron device blinking BLUE

In order to flash my code to the Electron device, I got the following messages:

! PROTIP: Hold the SETUP button on your device until it blinks blue!
? Press ENTER when your device is blinking BLUE

But it seems very difficult to get it. I hold the SETUP button for a long time, but I still cannot let the device blinking blue. I need to click the RESET button, sometimes I can flash the code successfully in this way.

But I don’t think it is the right way to do it.

Can you explain how to let the device blinking BLUE easily? Thanks.

I guess you are using particle flash --serial firmware.bin to flash your device.
What OS are you using to flash the device?

You could also use particle flash --usb firmware.bin to flash via DFU Mode (blinking yellow) which might be easier to get into, if you have problems getting into Listening Mode.

For getting into Listening Mode, your device should be already powered and in some “steady” state (e.g breathing cyan or constant blinking green or such) and then press’n’hold SETUP. After about 3 to 5 sec you should find your device in Listening Mode.

➜  Downloads particle flash --usb firmware\ \(54\).bin

Error writing firmware...dfu-util is not installed

How to install dfu-util? I am using Mac.

I guess this question was answered here