# Doppler is bricked?

**URL:** <https://forum.dadamachines.com/t/doppler-is-bricked/324>\
**Category:** FAQ / Support\
**Created:** [September 5, 2019, 4:52am UTC](https://forum.dadamachines.com/t/doppler-is-bricked/324 "2019-09-05T04:52:38Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![robertkb](https://forum.dadamachines.com/letter_avatar_proxy/v4/letter/r/b19c9b/32.png) [@robertkb](https://forum.dadamachines.com/u/robertkb)\
**Post date:** [September 5, 2019, 4:52am UTC](https://forum.dadamachines.com/t/doppler-is-bricked/324/1 "2019-09-05T04:52:38Z")

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I installed the board support packages for the Arduino IDE (Adafruit and dadamachines M4) and compiled and started to download the example sketch hex-lens-test. The download failed, and now the board is unresponsive; the serial port no longer appears in Tools/Ports. If I press the RST button on the board, the yellow LED flashes when I release it; that is the only sign of life. Does anybody have any suggestions about how to revive it?

A possibly related question- many of the examples contain the cryptic reference “see variant.h”. What is variant.h, and where can it be found?

Thanks,  
Robert

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**Author:** ![zmors](https://forum.dadamachines.com/letter_avatar_proxy/v4/letter/z/43a26b/32.png) [@zmors](https://forum.dadamachines.com/u/zmors)\
**Post date:** [September 6, 2019, 5:09am UTC](https://forum.dadamachines.com/t/doppler-is-bricked/324/2 "2019-09-06T05:09:18Z")

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double tap on reset button to enter in bootloader

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**Author:** ![robertkb](https://forum.dadamachines.com/letter_avatar_proxy/v4/letter/r/b19c9b/32.png) [@robertkb](https://forum.dadamachines.com/u/robertkb)\
**Post date:** [September 6, 2019, 5:25am UTC](https://forum.dadamachines.com/t/doppler-is-bricked/324/3 "2019-09-06T05:25:23Z")

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That worked, thank you!