Laird Sentrius RS1XX on TTN - Firmware update failure


I have used these units in the past and had no problems updating the firmware via mobile app to use with Cayenne/LPP rather than Laird proprietary payload (f/w 4.5 for obvious duty cycle benefits) . However, had a few units recently and during f/w update process stopped with error -
Updating bootloader - xxx of 1137 Error Task 8 failed: No response to opcode 0x04 OK

It makes the unit unusable - some units seem to respond by pressing down the BLE button for 30 sec and reset but others do not.

Anybody seen this or have an idea how to fix? Laird support contacted but no response.


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Just a quick update - this issue was experienced when using an ios device running software version 12.3.2 which seems to have been the issue. When I installed the Sentrius Mobile app on an iPhone with ios version 12.3.1 (I assume anything lower will work as well) the units successfully updated their firmware without hanging up. No support from Laird but suspect incompatibility somewhere.


I have the same problem firmware update with ios 12.3.1, It makes the unit unusable too…

Hi ccsmart,

Laird reached out to me today. No progress yet but will update you as soon as they indicate what the possible underlying cause is.

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Hi Brandberg

thank you so much

Very valuable info, thanks! I got nuts trying to update the FW again and again - and guess what, I am running iOS 12.3.1.

Used on older Android for the update which worked fine and can connect from my iPhone normally now.

Same situation for me.

My node at starting (just after putting the battery inside)
then on the phone

Always block here.
pressing BLE button have no effect.
Who could help me?

The error arrived because, I have try to downgrade the firmware from 4.5 to a another! The apk give you the option, but never do this!!!
Laird help center said me: “there is no way to flash firmware in your side”. But I see the 6 pins inside the battery compartment. I have a hope to update using these pins.
I ask the help center for files… waiting answer now.

So help center say me, "they is no way to flash firmware with 6 pin inside battery compartment.
The sensor will not allow downgrading the firmware over OTA. FW 5.2 and the corresponding update to the mobile app are being released next week. "

So waiting next week…

Hi all,

Laird support indicated to me that they think it is an application issue but no further details than that. Hopefully as kelu28 indicated FW 5.2 with corresponding app will solve the issue. I was fortunate that I did not try to downgrade the FW (did consider it) and then used an older iPhone with older iOS version and was lucky that this worked for me.
I am experiencing incorrect humidity readings on one sensor during my tests and suspect condensation on the sensor. Working on the heater control message to see if I can resolve the issue.

My RS186 is back to Farnell… Never work again.
But today I received a new RS186 with probe this time.455-0010.
So put the batteries inside the node, push on the bluethooth button and connect it with my phone.
And try to update.

I send a email to support…

So it is an application error ? :grimacing:

My NEW node is in DFU mode
I couldn’t do anything…
and then

I asked a colleague to lend me his iphone.
I installed the app.
and it worked. I made the update and I change the mode in Cayenne

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So Android App don’t work…

So i’ve got a similar issue i’m working through currently.

I purchased two RS191’s from Digikey America, into Australia. I figured i could assign AU915 to the units and they’d just work - not so… But anyway.

I’ve managed to upgrade one of my units by downloading the latest AU915 firmware using the latest version of the android app, then uninstalling that android app, and installing an old version of the app (because the old version doesn’t require PIN to change region/use test versions.

The update worked well, and i’ve now got my American US915 purchased unit running happily on AU915.

Unfortunately, the second RS191 that i have, i made the mistake of upgrading the firmware to the latest US915 version (thinking it might help me somehow). Well, it didn’t, and the old android app won’t flash this device with the latest AU915 firmware (or probably any firmware, as it doesn’t connect to the DFU of the RS191 at all).

Currently waiting on Laird support to provide me with a PIN so i can region change my second device to AU915…

Hi Deadpan, did you get anywhere with Laird?? I’m in exactly the same boat!!, thanks heaps, Dave.

If you’re looking to upgrade the firmware, it’s easy enough - as long as you have NOT updated the RS191 firmware to the latest version (or a recent version).

If it’s older - track down a version 3.x.x version of the android sentrius app (apkpure is what i used) AFTER you have downloaded the Au915 firmware on the LATEST version of the android app. Uninstall the latest version after you’ve downloaded the firmware, and then install the old version, and update away. Took all of 2 minutes…

If you’ve updated it to a recent firmware version, or it came with a recent firmware version already, i have been advised the only option they will support is sending it back to them to update the firmware - i even offered to sign an NDA to get the pin unlock code for their current software, which they also refused.

Looks like I have same/similar issue - after configuring/updating many of these units no problem over last year or two I finally have a brick!

Two solid leds same a @kelu28 near top of thread. In my case am using Android not IoS and have used same phone for many such updates, though I did see Google Play updated Sentrius App version recently (App version 5.0.0)… :thinking:

Unit took some time to connect over BT when 1st powered up - at least a couple of attempts and long waits each time. Eventually had it up in TTN App console and set up integration to Cayanne. Data was correctly decoded in TTN but incorrect in Cayenne dashboard (Temp @104/105 and hum -45ish!) usually solve this by swapping to use basic Cayenne LPP as ‘device’ vs the ‘official’ RS186 device set up on drop down menues. But as phone app was complaining device on old firmware (5.2.x.x?) and to update I figured change between switching set-up in Cayenne.

Device found the 5.4.x.x. firmware no problem and started in DFU mode and began updating Bootloader. Looked to get to around 50-60% complete (did I see 56/57%?) then saw a failed to run Task message similar to above - not sure if Task 8 or 9, on retry saw the Task 7 message same as above, now on start up it is stuck in DFU Mode, App not responding as awaiting the Device to respond (working fine with another unit I set u just afterwards (straight to Cayenne LPP mode on dashboard). And LED frozen on solid Green & Blue. I note they blick in sync briefly approx every 30 secs - so a watchdog or something still running?

Anyone know how to recover or do I have to send back to US Disty? (These are EU 868Mhz units) @deadpan Really dont want to go trawling for old apk’s etc. if that is only solution unless Laird send me something directly.

Full disclosure… not an engineer. I had the same problem with the Green/Blue LED turned on and fixed it. The problem occurred after I tried to update the firmware.


  1. Pulled batteries
  2. Updated App
  3. Installed new batteries
  4. Blinking still occurring…
  5. Open App
  6. App shows the device
  7. Click on device
  8. Select the device band
  9. That should update the device

Hope this helps