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leduypanda86

Hi,

I bought my Z1 in Australia 2 weeks ago and use it in Vietnam after that. For the first 2 week using it in Vietnam, the phone has worked just fine. Suddenly, 2 days ago when I turned on the phone, it cannot detect the SIM card anymore. I have tried different ways to find out what is the issue: replace another working micro SIM but the Z1 still cannot detect it, plug my SIM to another device and the SIM works well, factory reset the phone (using KitKat 4.4.2).

In fact, before getting this issue, I tried to deativate some core software in the phone (everything related to "social" term) because I thought my phone was quite hot and had fast battery draining issue (which have already been complaint by many users). After doing this, the phone became less stable, which means that after rebooting, there were 2 or 3 times it didn't get GSM signal but when I tried to factory reset the phone, the signal came back.

I wonder where the problem comes from? Because of hardware or software issue? If it's a hardware issue, the phone should be able to detect the SIM card after factory resetting, right?

By the way, the phone still asks me to enter the SIM card's PIN code everytime I boot the phone, which proves that the phone can still detect the SIM, somehow...

Regards,

Duy

leduypanda86

I recognize that when I flash older FW, the IMEI and Baseband become unknown, and the phone couldn't detect SIM card as well as connect to wifi. But now when I upgrade it to lastest FW (which is C6903 14.3.A.0.757), the IMEI and Baseband show. Thus, the phone can recognise the SIM card (by asking me to enter the PIN code) and wifi is usable. However, there is no signal at all, and there is nothing in APN,

leduypanda86

What I'm trying to do here is to flash back older ROM in order to get the "right" or "original" baseband when I used the phone at first time. I think the reason for this issue is that I use the phone in another country, when I upgrade the FW by OTA, the baseband changes, and the phone cannot read the SIM

_alexdon_

By SUS,you are not getting any signal?Try to flash 4.3.

alexdon

leduypanda86

Based on what I know, if I use SUS, the phone will upgrade straight to 4.4.2. Is there the way to use SUS to upgrade to 4.3?

If I use Flashtool to flash 4.3, because this phone comes from Australia, I chose C6903 14.2.A.1.136 Generic AU 1277-0078_R2B but it doesn't help, the IMEI and baseband are gone.