FSC-BT1036 (V2.8.7) — AT+PROFILE=17 (and 16 alone) rejected

MAUROfme

Hi all,

I'm hoping someone with FSC-BT1036 experience (or from Feasycom) can help, since I couldn't find direct support for this module.

Setup: FSC-BT1036, host = Microchip PIC18F26Q83, UART2 @ 115200 8N1. On every power-on the host configures the module with:

AT+PROFILE=17 (BIT0 SPP + BIT4 HFP-AG)

I have two units, same firmware version string, different production date:

Unit A (working)
AT+VER -> +VER=BT1036,V2.8.7,20260318
Boot events include +PROFILE=17 and +HFPSTAT=1 right away — value already persisted from a previous successful config, no write needed at runtime.

Unit B (not working)
AT+VER -> +VER=BT1036,V2.8.7,20260528
Boot events never include +HFPSTAT at all.
AT+PROFILE query returns +PROFILE=1 (SPP only).
Sending AT+PROFILE=17 is not acknowledged with OK, and a following AT+PROFILE query still returns 1 — the value never persists.
I also tried BIT4 alone (AT+PROFILE=16, no SPP), same rejection — so it's not a bit-combination/mutual-exclusion issue, it looks like HFP-AG itself isn't available on this unit.

Both units report the identical firmware version (V2.8.7), only the production date differs. The systematic absence of +HFPSTAT on unit B, plus the rejection of BIT4 alone, points to HFP-AG being disabled/unavailable at the module level on that batch, despite the matching version string.

Questions for anyone who has run into this:

Has anyone seen HFP support vary between BT1036 units with the same firmware version but different production dates?
Could this be a licensing/hardware-variant thing rather than a firmware bug?
Any known way to query/enable HFP-AG capability explicitly, or is it baked in at manufacturing?

I already have a ticket-style report ready to send to Feasycom directly, but wanted to check here first in case this is a known issue with a quick answer.

Thanks in advance for any pointers.

FAE_Gavin

MAUROfme Please note that the last part of the version string (e.g. 20260318 / 20260528) indicates the production date, not the firmware version. Both modules are running firmware V2.8.7.

As a first step, we recommend reflashing Unit B with the official V2.8.7 firmware to rule out any firmware-related issues.

Firmware Upgrade Guide
DFU Name:BT1036/audtxrx/287

If the issue still persists after the upgrade, please enable the debug log by sending:AT+EHCO=2

Then repeat your configuration steps (including the AT+PROFILE commands) and send us the complete log output. This will help us analyze why the HFP-AG profile cannot be enabled.

We look forward to your test results.

MAUROfme

Thanks for the reply. I'll run the suggested tests today and post the results.

MAUROfme

Hi Gavin,

I have carried out the checks: I have a batch of 10 pcs with firmware V2.8.7 that do not accept the PROFILE=17 command, while they do accept the other profiles.

I cannot load the firmware from your website, because these modules are already mounted on a board and the AT commands are sent by a microcontroller.
It would be extremely complex to modify the firmware of our microcontroller in order to send the commands, and all the units in the faulty batch are already mounted.

How can this be explained? Is this a repeatable defect?

I need to order thousands of these modules, and once they are mounted, if they show this defect I would have to scrap an expensive PCB.

One last question: is there a Feasycom tool to test the modules easily, without soldering?

Thank you in advance for your support.

FAE_Gavin

MAUROfme After further checking with our team, we found that there are actually different firmware variants under BT1036 V2.8.7, depending on the required audio function.

The reason why AT+PROFILE=17 cannot be enabled on your modules is that your current modules are running the audio receiver firmware version (audrx).

AT+PROFILE=17 enables:

BIT0: SPP (Serial Port Profile)
BIT4: HFP-AG (Hands-Free Profile Audio Gateway)

HFP-AG is related to the audio transmitter/gateway function. Therefore, modules with the audrx (audio receiver) firmware cannot enable this profile.

To check the firmware type, please enter:AT+HELP
The firmware type will be shown in the help information:

audrx → Audio Receiver version
audtx → Audio Transmitter version
audtxrx → Audio Transmitter + Receiver version

For your application, since you require AT+PROFILE=17, you need the audtxrx (transmitter + receiver) firmware.

You can upgrade the module firmware to:

DFU Name: BT1036/audtxrx/287

Firmware upgrade guide:
https://document.feasycom.com/docs/fsc-audio/EN/latest/bt1036x/8-firmware-upgrade.html

Regarding your future orders, please make sure to inform our sales team of your complete application requirements, especially that you need both audio receiving and transmitting functions (audtxrx), so the correct firmware version can be programmed before shipment.

For the evaluation/testing purpose, you can also use FeasyBlue to upgrade and test the module firmware more conveniently.

MAUROfme

Thank for your replay.
I tried updating the firmware via OTA, but it doesn't work. It always gets stuck around 40%. Could you send me the DFU file so I can update it via FLASH instead? Thank you

FAE_Gavin

MAUROfme We recommend powering off the module and re-enabling your phone's Bluetooth before attempting the firmware upgrade again. Alternatively, you can try testing with a different phone.

If the upgrade still fails, please record a video and send it to support@feasycom.com. We will then help you troubleshoot the problem.

MAUROfme

Here's the English translation for the forum post:

Along with the request for the UART upgrade tool/firmware file, I'd like to report the following behavior: the OTA upgrade consistently stalls at the exact same percentage on every attempt. At the point of failure, the phone shows the Bluetooth connection to the module as dropped, yet the module itself remains fully alive and responsive to AT commands immediately afterward, with no power cycle or reset required. This is a precise and reproducible technical report, not an intermittent app-side glitch.

Could you confirm whether the FSC-BT1036C's OTA mechanism uses a single flash bank (which would make it more exposed to this kind of issue, if a flash erase/write operation blocks the radio scheduler long enough to trip the phone's connection supervision timeout), or whether there is a firmware revision with improved handling of flash erase during OTA? With these details you should be able to either confirm the root cause or point us to an existing fix.
Please send me the file to update via UART.

MAUROfme

I keep noticing that during the OTA the Bluetooth connection repeatedly drops and reconnects throughout the whole transfer, not just once at the point of failure — it seems to be a recurring pattern rather than a single isolated event.

MAUROfme

I've tried with all the phones available. This is extremely urgent, please — I have a batch of 7 units stuck with the wrong firmware. Please give me the possibility to use the UART.

FAE_Gavin

MAUROfme

bt1036-audtxrx-20260205-bl-100-app-287-update.zip

513kB

The file has been uploaded. Please extract it before use. For upgrade instructions, please refer to:https://document.feasycom.com/docs/fsc-audio/EN/latest/bt1036x/8-firmware-upgrade.html#uart-upgrade