FW Update from 533 -> 538


After finishing a couple roasts I finally thought to check for f/w updates and was surprised to see one was available. Since the Bullet was in OFF mode I started the update and got the “… must be in OFF mode…” message which then cleared itself.

The update went fine. In fact it was noticeably faster than the last couple updates. Then the fun began-

  • I cycled power 2x and disconnected/reconnected the USB port. But no number of cycles could bring life back to the Bullet.
  • Jumpered SDA to Gnd and powered up, then cycled power & USB a couple times. No joy… the control panel was dead (should have anticipated this since the jumper forces the boot loader on… oops!)
  • Jumpered SDA to Gnd again and powered up, then d/l’ed f/w again. This time things went as expected and the Control Panel lit up after I cycled power a couple times.
  • The Info panel took another power cycle to get it to update the number of roasts properly… that’s 3 power cycles in all to get data sorted.
  • When starting to d/l f/w, there were a number of error messages including the one about being in OFF mode. This time the messages didn’t go away. Neither did they interfere with d/l’ing f/w… just kept on like I knew what I was doing.
  • After all the floundering things seem to have initialized properly (but no roasting yet to confirm it).

I posted this only because I understand there has been some work in this area. Nothing catastrophic happened, but neither did it go as smoothly as I recall when I first got the Bullet 10 months ago.


Roaster unresponsive and no display

I think I like my 515 even better after reading this. Thanks for checking it out. Look forward to hearing you had a successful roast.


As I have a v1.5 110v model I have stopped chasing firmware updates - I’m led to believe that most of the recent ones relate to the V2 model/boards.


It’s my impression there have been annoying issues with the first startup after f/w update for the last 4 or 5 (?) updates. Initially f/w updates were a breeze, but now… not so much. Other than one disastrous episode with simultaneous s/w & f/w changes I’ve been able to recover OK. Of course I may wear out the screw threads on the Control Panel! :slight_smile:

That’s my understanding as well, Stuart- fixes for the V2 power board. If I had 240 VAC available where I roast I’d likely have gotten the new board by now. Now I’m pretty happy I’m limited to the 120 VAC board. I’ll definitely get the V2 120VAC power board when it becomes available even though I have no compelling reason to roast 1 kg of greens at one time. Other than needing to clean the IBTS after 3 or 4 roasts (!), I’m pretty happy with the V1.5 Bullet and that won’t change by going to V2.



@bab - Are you on the V1.5? I am and had over 500 roast on mine and never had to clean the IBTS once. The fan failed on it and Aillio send me a new IBTS. Now I have to clean the sensor ever 3 or 4 roast as well.

It just seems super odd. Nothing changed other than the IBTS. I am dropping the same batch size of the same beans.

Any thoughts on why it might need cleaned so much?



Hi John-

Yes… V1.5. I have far fewer than 500 roasts. I probably had 70+ roasts of either 600 or 300 gm the first time I cleaned the IBTS and I saw no difference in IBTS reading at FC (& SC). A couple sessions later I cleaned it again thinking I hadn’t done a good job the first time and sure enough- I saw a significant difference in IBTS measurement after the second cleaning. I thought there was no difference in how I did the cleaning, but something had to be different. Neither the first nor the second time I cleaned did I actually see anything on the cotton swab, but there was a difference in how the IBTS measured after the second cleaning.

At first I first speculated evaporated oil from the drum was settling on the IBTS lens while the IBTS fan is off (Bullet in storage), so I started leaving the dump door prop’ed open when the roaster was being stored. I don’t see any difference… still see IBTS temp drift down at FC (& SC) with each roast.

I’ve been told by Aillio (Jacob) that they have seen returned IBTS fans (like yours I suppose) with smoke particles on the fan blades. They speculated there was exhaust smoke being picked up from outside the control panel housing via the air inlet. They wondered if a filter might be in order (I presume he meant over the air inlet grill).

Armed with that for background I started looking around for some filter material to kluge together a filter to cover the air inlet. That air inlet is very close to the dump door for the drum, so some smoke or maybe evaporated oil could be picked up from the still-hot beans as they drop into the cooling bowl. Whatever I pick has to not restrict air flow to the high-speed fan. My thought is to try some pleated paper from a larger air filter. I doubt mesh (like the ScotchBrite in the bean cooling tray) or open-cell foam would be effective.

I’m saying more than I really know… just expanding on what I picked up from Aillio a month ago.



Can you take some photos of the installation of the IBTS? Is it completely flush with the silicone adapter?