# Can't flash firmware

**URL:** <https://forum.unphone.net/t/cant-flash-firmware/16>\
**Category:** unPhone programming\
**Created:** [11 January 2023 18:57 UTC](https://forum.unphone.net/t/cant-flash-firmware/16 "2023-01-11T18:57:10Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![alter.ego](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@alter.ego](https://forum.unphone.net/u/alter.ego)\
**Post date:** [11 January 2023 18:57 UTC](https://forum.unphone.net/t/cant-flash-firmware/16/1 "2023-01-11T18:57:10Z")

</div>

Trying to flash firmware but getting nothing from the board…

---

<div class="post-metadata">

**Author:** ![hamish](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.unphone.net/hamish/32/3_2.png) [@hamish](https://forum.unphone.net/u/hamish)\
**Post date:** [11 January 2023 19:00 UTC](https://forum.unphone.net/t/cant-flash-firmware/16/2 "2023-01-11T19:00:45Z")

</div>

Things to check:

- The first time we burn firmware to a new board, we need to manually put it  
into boot mode by holding button 2 and momentarily pressing reset  
(otherwise, although the OS sees the port, esptool will not be able to write  
to it); sometimes the device goes back into that state (or is in a bootloop  
that prevents upload), and requires the same hold button2/touch reset  
combination to fix.
- Note also that the unphone9 port will usually appear as /dev/ttyACM0 in  
ubuntu; sometimes it shifts over to ACM1 or ACM2 when resetting, so if  
encountering problems writing to the board try changing the port (and/or the  
above).