Exhaust Fan Running and nothing much else


Dear Aillio,

I just updated my firmware (not sure if this was a coincidence) and having a problem upon start up. The exhaust fan is running but the front display is blank and doesnt light up at all.

I already checked fuse and seems to be intact.

Can you please help

Many thanks



I ran into the same issue while updating the firmware. It turns out that the Bullet gets stuck in a weird state.

The only thing that could fix it was by manually setting it to firmware update mode.

  1. Unplug power and USB.
  2. Remove the display panel front.
  3. Connect “GND” and “SDA” (you should probably use a multimeter but I just used a paper clip).
  4. Connect power, start up the Bullet. You should hear 4 beeps (this indicates FW update mode).
  5. Disconnect “GND” and “SDA”.
  6. Plug in USB and then open RoasTime. In my case the Bullet is shown as “connected” and I could retry updating the FW.



Hey - this sounds like what is happening to me - no lights on the control board, but unit powers up, but exhaust fan and PCB board fan go on ‘full’ - computer does not recognize USB - does this sound similar? can you clearify the ‘connect GND & SDA’ piece - I have found the marked holes - do I just stuff a paperclip in? Thanks so much for any help!

Aillio support are you able to confirm this is a safe and reasonable fix?


Best go to the Aillio site. Under Support find the .pdf for forcing the Bullet to boot mode. You are doing this to allow f/w to be reloaded… the thought posted here is that the f/w is corrupted. It’s best if you have a helper to deal with power while you hold the jumper in place and try to not short something unintentionally.


Ps- points out the need for a power switch. I have an external power control box for this situation.