Junsun V1 Pro - Sim card 4G issue

[the_moom]

Hi everyone,

I've got an Junsun V1 Pro head unit with the latest firmware (8259P_军灿UI02v1280x720-国外_v50_20221226) installed in my car. Now I‘m facing an issue with my sim card for the car. When I install the sim card the first time everything works as expected. Internet is working and connection is 4G (even VoLTE). But when I turn on the head unit after standby, the connection is reestablished only with 2G (at the exact same location). The sim card is from sim.de and is operating in the O2 network and as multi card.

• Tested with klarmobile sim card (Vodafone network): Every time 4G
• Tested sim.de sim card in Huawei Gigacube: No problems
• Checked and adjusted APN settings: No effect
• Disabled VoLTE: No effect
• Changed setting between 2G / 3G / 4G: No effect

Are there any known issues with Junsun and the O2 network?

kind regards
Markus

 

[TorstenH]

Hi everyone,

I've got an Junsun V1 Pro head unit with the latest firmware (8259P_军灿UI02v1280x720-国外_v50_20221226) installed in my car. Now I‘m facing an issue with my sim card for the car. When I install the sim card the first time everything works as expected. Internet is working and connection is 4G (even VoLTE). But when I turn on the head unit after standby, the connection is reestablished only with 2G (at the exact same location). The sim card is from sim.de and is operating in the O2 network and as multi card.

• Tested with klarmobile sim card (Vodafone network): Every time 4G
• Tested sim.de sim card in Huawei Gigacube: No problems
• Checked and adjusted APN settings: No effect
• Disabled VoLTE: No effect
• Changed setting between 2G / 3G / 4G: No effect

Are there any known issues with Junsun and the O2 network?

kind regards
Markus

I'm using the same firmware and today I ordered an O2 SIM. I will let you know if I will run into the same problem.

 

[TorstenH]

You could try after sleep mode:

Disable and enable mobile data.

Enable and disable flight mode (maybe via search function in settings app).

Does it help to bring 4G back?

 

[the_moom]

You could try after sleep mode:

Disable and enable mobile data.

Enable and disable flight mode (maybe via search function in settings app).

Does it help to bring 4G back?

No, unfortunately not.

Yesterday I tried to increase the pressure on the sim and added a small piece of cardboard. It worked the whole evening, even after standby. But today it stopped and is back to 2G.

 

[TorstenH]

No, unfortunately not.

Yesterday I tried to increase the pressure on the sim and added a small piece of cardboard. It worked the whole evening, even after standby. But today it stopped and is back to 2G.

Unfortunately my SIM card still not arrived so I can't tell you if it works on my device / with my O2 SIM.

I can't imagine that it's a topic of bad electronically contact because the issue only occurs after sleep mode.
One possibly could be to compare the units processes before and after sleep mode.

1. Stop all apps to avoid unneeded programs occure in the list
2. List all processes running
3. Put the unit in sleep mode and wake it up
4. If you only have 2G list all running processes again

Maybe a service doesn't comes up after sleep mode which is relevant for 4G data connection.

 

[TorstenH]

I added the SIM card today and two reboots were required to get 4G.
I put the device into sleep mode (just a few minutes) and had still 4G.

Let's see how it is after a long sleep...

 

[the_moom]

I added the SIM card today and two reboots were required to get 4G.
I put the device into sleep mode (just a few minutes) and had still 4G.

Let's see how it is after a long sleep...

Does it work?

 

[TorstenH]

Does it work?

It works (not always).

This morning after wakeup the head unit displayed "no sim card" on the bottom of the mobile data icon in status bar.

After reboot it worked fine, so it was not a contact problem of the sim card holder...

 

[TorstenH]

I found this:
Post in thread 'Auto-toggle SIM card (e.g. with Tasker, adb shell)' https://forum.xda-developers.com/t/...g-with-tasker-adb-shell.3656963/post-73482775

This may be an approach to disable/enable the Sim. If you're willing to test I can write a small app doing the job.

 

[TorstenH]

After serveral days usage I have exactly the same issue:

After (longer) sleep only EDGE or even message "no Sim".

Changing mobile data settings or changing to flight mode not bringing back 4G. Reboot is the only way to get 4G again.
I don't think it's hardware related because it works after reboot without touching the Sim card dongle.

I will investigate the Android log. @the_moom you may want to do the same?! Four eyes may see more that two.

 

[TorstenH]

I compared the running system services after sleep and after reboot. Found no difference...

So next step is to check logcat...

 

[TorstenH]

It may help to restart the RIL daemon...

adb shell stop ril-daemon
adb shell start ril-daemon

I will test this tomorrow...

 

[TorstenH]

It may help to restart the RIL daemon...

adb shell stop ril-daemon
adb shell start ril-daemon

I will test this tomorrow...

Restart of vendor.ril-daemon-mtk isn't sufficient.

 

[le_mi]

Is the SIM protected by PIN?

 

[TorstenH]

Is the SIM protected by PIN?

I switched off the "pin required" setting. Or is there are way to remove the pin from the card?

 

[le_mi]

I switched off the "pin required" setting. Or is there are way to remove the pin from the card?

I had put the SIM in the smartphone at the beginning and disabled the PIN.

 

[TorstenH]

I had put the SIM in the smartphone at the beginning and disabled the PIN.

As it's done in this video? Or is there another way?

 

[le_mi]

As it's done in this video? Or is there another way?

Correct in this way.

 

[TorstenH]

Correct in this way.

I used this setting - but directly on the head unit.

 

[le_mi]

I used this setting - but directly on the head unit.

Well then i think this is not the reason for the issue.