Trouble connecting an AquaLung i300c with Subsurface-mobile via Bluetooth

[Nicolas Matringe]

Hello

I've been happily using Subsurface for a few years now, but lately, I've
ben unable to download my dives.

The last dives I've managed to download were in early march. I
dived again in may, and couldn't download the dives, and haven't
been able since.
I installed DiverLog+ and it works just fine, so I guess the problem is
not with the hardware...

On my Windows PC it never worked.

Thanks for any help or tip
Nicolas

[Michael Keller]

Hi Nicolas.

On Sat, 6 Jun 2026 at 05:40, Nicolas Matringe <nmat...@gmail.com> wrote:

I've been happily using Subsurface for a few years now, but lately, I've
ben unable to download my dives.

The last dives I've managed to download were in early march. I
dived again in may, and couldn't download the dives, and haven't
been able since.

What version of Subsurface are you using, and on what device / OS version?

Are you aware if any firmware updates were installed on your dive computer?

 

I installed DiverLog+ and it works just fine, so I guess the problem is
not with the hardware...

That's a start. You should be able to export dives from DiverLog+ as UDDF, and then import them into Subsurface as a temporary solution.

Ngā mihi 

  Michael Keller

--

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W++ N o? K? w O(++) M-- V+ PS+ PE+ Y? PGP+ t
5? X R tv b++ DI++ D++ G e+++ h---- r+++ y+++

[Nicolas Matringe]

Hello Michael

I'm using Subsurface Mobile version 6.0.5612.0 on an Android device. No updates were installed on the dive computer.

I tried reinstalling Subsurface but it didn't solve anything and removed all the dives from my mobile (they're still saved on the laptop)

Exporting from DiverLog+ doesn't seem so straightforward but I'll give it a shot.

Thanks !

[Michael Keller]

Hi Nicolas.

On 09/06/2026 06:20, Nicolas Matringe wrote:
> Hello Michael
> I'm using Subsurface Mobile version 6.0.5612.0 on an Android device.
> No updates were installed on the dive computer.
> I tried reinstalling Subsurface but it didn't solve anything and
> removed all the dives from my mobile (they're still saved on the laptop)

Try this:

- try downloading the logs from your dive computer

- go to the Help menu;

- tap 'Ask for support';

- send the automatically generated email (which will include your debug
logs and system information) to the developers.

> Exporting from DiverLog+ doesn't seem so straightforward but I'll give
> it a shot.

Yeah, it's not great, but it will tide you over until we've been able to
figure out why this isn't working for you.


Ngā mihi

  Michael Keller

[Michael Keller]

Hi Nicolas.


On 10/06/2026 22:16, Nicolas Matringe wrote:
>
> I can't download the dive data from my AquaLung i300c. It used to
> work, up until march.
>
>  The dive computer hasn't been updated and I can download the data
> using DiverLog+ instead of Subsurface.


Thank you for the log files - it looks like the dive computer is
stopping to communicate with Subsurface before logs can be downloaded:

22.932: DCDownloadThread started for Aqualung i300C on
LE:CF:00:00:00:78:C0 downloading only new dives
Starting download from BLE
downloading only new dives
22.942: setProgressMessage: Connecting to BLE device LE:CF:00:00:00:78:C0
---> stopping the discovery agent
Creating Android Central/Client support for BTLE
qt_ble_open(CF:00:00:00:78:C0)
QLowEnergyControllerPrivate setting state to
QLowEnergyController::ConnectingState
timeout while trying to connect to the controller CF:00:00:00:78:C0
Timeout while trying to connect to CF:00:00:00:78:C0
QLowEnergyControllerPrivate setting state to
QLowEnergyController::ClosingState
34.982: Timeout while trying to connect to CF:00:00:00:78:C0
QLowEnergyControllerPrivate setting state to
QLowEnergyController::UnconnectedState
34.988: setProgressMessage: Import error: Input/output error


This could be because there is too much 'noise' - make sure there are no
other bluetooth devices in the vicinity, and then try again.


Ngā mihi

  Michael Keller

[Nicolas Matringe]

Hi Michael

Le 11/06/2026 à 01:48, Michael Keller a écrit :
> [...]

>
> This could be because there is too much 'noise' - make sure there are
> no other bluetooth devices in the vicinity, and then try again.

I did try to download again. I unfortunately don't have acces to an
anechoic chamber anymore, so I just tried at home and it didn't work any
better. However, in the exact same conditions (unless some BT noise
generator suddenly fell silent at the exact moment I tried), it worked
just fine with DiverLog+. Same DC, same Android phone, same setup, the
only difference being the app.

Is there any way I can install an older release of Subsurface (pre-march
2026) and maybe the subsequent ones, so I can try and pinpoint which one
broke the i300c support ?

Thanks
Nicolas

[Dirk Hohndel]

> On Jun 13, 2026, at 07:58, Nicolas Matringe wrote:
>
> I did try to download again. I unfortunately don't have acces to an anechoic chamber anymore, so I just tried at home and it didn't work any better. However, in the exact same conditions (unless some BT noise generator suddenly fell silent at the exact moment I tried), it worked just fine with DiverLog+. Same DC, same Android phone, same setup, the only difference being the app.
>
> Is there any way I can install an older release of Subsurface (pre-march 2026) and maybe the subsequent ones, so I can try and pinpoint which one broke the i300c support ?
>

Older releases are available on our downloads page (not the download page... you need the plural to get to the file listing) and on the GitHub nightly-build repo

/D

[Nicolas Matringe]

Le 13/06/2026 à 18:11, 'Dirk Hohndel' via Subsurface Divelog a écrit :
> Older releases are available on our downloads page (not the download page... you need the plural to get to the file listing) and on the GitHub nightly-build repo

Thanks Dirk.

So I reinstalled version 6.0.5504, and managed to download the dives.
More recent versions didn't work. So I decided I'd go with the one that
worked, and now it doesn't work anymore. No matter what I do, turn BT
off and on again, remove the DC from the BT devices list... Timeout
everytime.

Side note : the display doesn't adapt to the phone screen in versions
post-5504.

Nicolas

[Michael Keller]

Hi Nicolas.

On 15/06/2026 03:13, Nicolas Matringe wrote:
> So I reinstalled version 6.0.5504, and managed to download the dives.
> More recent versions didn't work. So I decided I'd go with the one
> that worked, and now it doesn't work anymore. No matter what I do,
> turn BT off and on again, remove the DC from the BT devices list...
> Timeout everytime.

Just for testing's sake, have you tried uninstalling and then
reinstalling 6.0.5504, to check if it working the first time round was
significant, or if this was just a random coincidence in a flaky process?


Ngā mihi

  Michael Keller

[Nicolas Matringe]

Hi Michael²

Le 14/06/2026 à 22:24, Michael Keller a écrit :
> Hi Nicolas.
>

> Just for testing's sake, have you tried uninstalling and then
> reinstalling 6.0.5504, to check if it working the first time round was
> significant, or if this was just a random coincidence in a flaky process?
>

After a few unsuccessful attempts, here is what just worked :

- Reboot the phone (did it a few days ago after some problems with
another totally unrelated BLE device). That didn't solve the problem
with Subsurface but it may have helped.
- Deinstall Subsurface
- Remove the dive computer from the phone's BT devices list
- Turn phone BT off
- Turn DC BT off
- Reinstall Subsurface 6.0.5504
- Turn DC BT on
- Turn phone BT on
- Pair the DC with the phone
- Launch Subsurface and while the DC is still displaying "BT PAIR",
start downloading the dives

Nicolas