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UF896 7minutes problem #9
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Try adding a heatsink or active cooling, these devices run hot. I used silicone thermal pads on mine.
The |
Thank you for the fast answer! Yes, I decompiled dtb file into dts file using dtc but I do not see any pin for SIM card, but I can see at the end pins for LEDs. |
According to this, there is no sim select for UF896. Have you tried another dongle? It could be a hardware issue too. |
It is a bit strange:
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If you have a working kernel from another firmware, you can easily use them here. Just copy the |
thank you for help, but what you suggest probably would not solve problem, here is why: yesterday I made 2 tests: I put modem into freezer then out on the window (temp was -3celsius) and after 7 mins disconnected this behaviour is the same for all possible systems, debian, 2x openwrt (different forks) and also original Android I think you know well debian, if you could tell me which log and where to see, eventually another way of digging this problem I would try it as I said yesterday, I tried openwrt with exchanged EN and SEL in dts and no change (I am not sure it was really compiled with exchanged signals, I have to find how to get dtb from openwrt, it is not anywhere......) I suspect there is a problem with ModemManager and it is copied everywhere from the same origin.... I think |
I verified that I correctly exchanged and recompiled OpenWrt:
NORMAL:
EXCHANGED pins:
So it means I did it correct. Question is if I changed pins that control SIM card??? I will try to exchange sim and sim2 if it stops working!? |
This shows that UF896 does not use the sim select pins. Try another way of checking the hardware:
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yes, you are right in this:
I already made temp test and it is not temp problem, see above Do you know where in source code the SIM is handled? Because one guy (see above) proved already different hardware with exchanged pins |
No idea where the SIM handling is done, maybe it's done by the Qualcom firmware. |
I have discovered something strange, this could be the problem: Later I dicovered that mmcli reads "no sim card". I measured VCC and it is only 1.8V. The card in reader with 5V normally replies ATR. I think there is something wrong with selecting VCC for SIM? |
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Yes, I believe this is the problem. Even before this I did not know why one old SIM card is not recognized in the modem. (I soldered small SMD led with SMD resistor 10kOhm on SIM on VCC and voltage is lower than 2.2V all the time, modem does not increase not even to 3.3V, not to 5V) |
I spent today whole day measuring the staff. It is modem that deceives us. It is NOT true "Sim missing" I measured Power, Data and Reset signals (from top to bottom) All SIMs I have really work on 1.8V and modem DOES know it is not needed to increase the voltage. Because all SIMs I tested communicate with modem. But for some modem reads "Sim missing" - absolute nonsense. Attached are waveforms for "sim missing" but you can see it answered ATR and then communicating a long long time....... I do not know why modem claims for some sim cards they are missing but they DO communicate!? Attached is a long time record and first byte of ATR 0x3B after Reset released to log1. What the heck is going on?! I am sure this is also answer why modem drops connection after 7 minutes. |
Do you have another modem to test? Do note that majority of these boards use recycled components. |
Unfortunalety I have only one. But I have different types that are only NDIS modems which need some computer, they are usb sticks. In these all sim cards I have are "visible" I believe no usb openstick (UF896, UZ...., and so on) work Or problem is really on my side. I use "modem.bin" from my stick which had Android. Could be that I transfer 7-min problem with this modem file. I will go back to Android I have backup and try to root it to make some analysis. Could be that this modem file is also responsible for "sim missing" problem |
You need to test with the original firmware first. If that fails, it's either a firmware or hw issue. The sticks I own has no modem issues. The only problem that I've encountered are flash failures (due to recycled chips). |
Does your modem have a battery? If the modem does not have a battery, then stable operation can only be achieved when powered from an external source, not from the computer's USB. I modified the USB cable (connected an external power supply) for FY_MF800 and now disconnects happen very rarely (once a day). I removed the battery, since its charging does not work adequately on Debian. |
Hi, I and some other people have the same problem. I tried original Android (never worked well), two different OpenWrt and this Debian.
Problem is that modem disconnects from ISP after 7..8 minutes. So it works only for 7 minutes.
I suspect that it could be the SIM card is rechecked if still present in modem.
I also read somewhere that SIM_SEL and SIM_EN are exchanged. (so probably seller flashes incorrect FW)
So I believe it might be that after power on SIM is available due to all signals active. Then if it wants to reaktivate SIM it crashes?
Is it possible to exchange in source code these 2 signals? I tried to find but there is no *.dts file for UF896.
Thanx!
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