SM-G920F "emergency calls only" "No Network" very strange problem - GSM-Forum

rafick · 02-20-2016, 22:18

I have Samsung S6 (SM-G920F) brand new. Story goes... It has previously been sent to cowboy 'repair shop' to have it unlocked and the shop messed up. They returned it with IMEI showing 35000000000006. The original EFS has been lost but I quickly did a backup of EFS & security with Octoplus and when I restore the 'original' EFS the IMEI is 35000000000006. Also, recovery mode shows "dm verity verification failed need to check DRK first" after latest update via Smart Switch using "recovery and initialization" option but it hangs on Samsung logo but it does go through fine when the phone is rooted using S6_UniKernel.

I solved all those problems above and now the phone has original serial number with a working/tested IMEI and flashed with 4 file firmware 5.1.1 (G920FXXU3COI9_G920FBTU3COJ1_BTU) the only firmware that works with Odin. All other firmware in the support area fails using Octoplus. I tried so many other 5.1.1 firmware files, certs, and EFS files from working S6 models, just incase and all seems to go well.

The phone shows correct serial, IMEI, and all other functions work fine...

BUT... the phone ONLY shows "emergency calls only" "No Network". However, it does nearly always pick up the name of the Sim-card service provider on start up and in the settings under 'Access Point Names'. The Signal bars seem to be there but no 4g or H+ or 3G ever shows. When I scan for "mobile networks" manually, it sometimes finds the network operators but always fails to connect to network. IMEI status OK in service mode.

Settings > status shows: network: unknown > Service status: Out of service > mobile network state: disconnected. But the phone pops up with name of network operator of which ever Sim-card in insert. Very strange.

Have been working on it for 3 days straight but unable to figure it out. Any help will be appreciated.

Octopus box · 02-22-2016, 10:05

Hello.

Try to make an "Unlock" operation, then try to find and select Network manually.
Note: You should remove SIM card from the phone before performing the operation.

Quote:

the phone is rooted using S6_UniKernel

This fact might cause problems with an "Unlock" operation. We recommend to use CF Auto Root, to root SM-G920F.

rafick · 02-22-2016, 12:08

Thanks for your reply/suggestions.

I have now rooted the phone with 'CF auto root' and removed the Sim-card to do an unlock process again. All went well no problems, but the issue remains the same. When I manually select network it finds a few and when I select the correct one it says "the selected network in unavailable" "not registering on network" try later, nor matter which Sim-card/network I use (all working Sims). I get "emergency calls only" all the time. The strange thing is that is picks up the service provider on boot up and asks me to select the correct network. It also picks up the voicemail on one Sim-card but obviously I can't dial out.

I have had this sort of problem before with other Samsung models (S4, S3... etc) and I used to flash a 'custom modem' file or use 'network repair' option or 'flash the QCN' files to resolve such problems. But with the Samsung S6 (SM-G920F) these options are not available in any of the repair boxes because I think it's a new qualcomm?

I need something similar for the SM-G920F.

Octopus box · 02-22-2016, 12:43

SM-G920F is Exynos-based phone and doesn't have a QCN.

Please perform "Read Cert" operation, then try to writ a Cert file from the Support Area. Check whether phone obtains Network after writing of a Cert file.

rafick · 02-22-2016, 20:02

Have just tried new certs but same results. The certs work fine on another S6 phone.

I have installed "service mode" apps from app store and also installed 'Phone info' app. What I have noticed in the 'CSC CODE' section is that the Product code is blank (missing) others are all there - BTU, country, mobile operator etc

Is this a clue? and how can i fix this? I can't seem to find any other faults.

Thanks again for all your help.

Octopus box · 02-23-2016, 11:11

In order to fix problem with CSC try to reflash the phone. You might need to root the phone, if it will have issues with turning on after writing of a firmware. We recommend to use CF Auto Root, to root SM-G920F.

rafick · 03-03-2016, 19:02

I have tried to re-flash a number of different firmware files but the problem remains.

I was able to temporary remove the "dm verity verification failed need to check DRK first" error message by flashing the 4 file firmware (5.1.1) and then it will get stuck on the Samsung logo, but again by flashing the same firmware but only the AP file below:

(AP_G920FXXU3COI9_CL5816106_QB6438203_REV02_user_l ow_ship.tar)

However, even with official firmware and not rooted the phone still has "emergency calls only" "No Network" error. The phone finds the network but no signal (cert is fine)

I done a check using Phone info app and it shows this:

Not sure if this information is helpful?

Octopus box · 03-04-2016, 11:09

Unfortunately, if You have refurbished phone, we can't say what exactly can cause issues with Network without having the phone on hands.

rafick · 03-04-2016, 12:20

Quote:

Originally Posted by Octopus box

Unfortunately, if You have refurbished phone, we can't say what exactly can cause issues with Network without having the phone on hands.

Okay, I understand. Hopefully someone will read this thread and confirm if the phone has missing 'Manufacturing date' and 'Hardware revision' then it will cause No signal/emergency calls only error. Could it just be the phone-info app not being very accurate in it's report?

Thanks for your help, strange as the phone is brand new condition, I will just wait it out...

rafick · 03-22-2016, 22:14

Just an update:

I decided to remove and replace the motherboard to reuse the 'brand new' screen and housing... and to my surprise I found that the motherboard was lightly water-damaged. I have cleaned the areas but have not tested the motherboard again. However, the question to my main problem "emergency calls only" "no service" has been answered. The baseband IC or other component[s] to do with signal maybe damaged. The Phone info app reported false information due to hardware problem. I hope this thread helps other people

allumts · 03-23-2016, 00:13

Remember Always that Many of these APP also from Original PlayStore are developed by FAKE Peoples, if you will have read Last Info about 100th of APP from google Play Store "CRAMPED" you will have had most knowledge and NEVER use APP for try to repair one Phone like you model.

Also Flash EFS from other Same phone isn't Good procedure....this is last attempt when have tryed in all mode of solve more advanced issue, not for Network where same Cert work fine in other same model.

Is obvius that from you history is HW problem.

I had one issue with one G925F accepting All fw , root, Kernel, Sboot, modem itc...but Always in Boot Loop, at the end after 4 days tryng via Sw have open phone and the problem was in the Flat of microusb connector, replaced this finish the Boot Loop and all other problem

BR
allumts

02-20-2016, 22:18	#1 (permalink)
rafick Crazy Poster Join Date: Oct 2003 Posts: 56 Member: 40884 Status: Offline Thanks Meter: 4	SM-G920F "emergency calls only" "No Network" very strange problem I have Samsung S6 (SM-G920F) brand new. Story goes... It has previously been sent to cowboy 'repair shop' to have it unlocked and the shop messed up. They returned it with IMEI showing 35000000000006. The original EFS has been lost but I quickly did a backup of EFS & security with Octoplus and when I restore the 'original' EFS the IMEI is 35000000000006. Also, recovery mode shows "dm verity verification failed need to check DRK first" after latest update via Smart Switch using "recovery and initialization" option but it hangs on Samsung logo but it does go through fine when the phone is rooted using S6_UniKernel. I solved all those problems above and now the phone has original serial number with a working/tested IMEI and flashed with 4 file firmware 5.1.1 (G920FXXU3COI9_G920FBTU3COJ1_BTU) the only firmware that works with Odin. All other firmware in the support area fails using Octoplus. I tried so many other 5.1.1 firmware files, certs, and EFS files from working S6 models, just incase and all seems to go well. The phone shows correct serial, IMEI, and all other functions work fine... BUT... the phone ONLY shows "emergency calls only" "No Network". However, it does nearly always pick up the name of the Sim-card service provider on start up and in the settings under 'Access Point Names'. The Signal bars seem to be there but no 4g or H+ or 3G ever shows. When I scan for "mobile networks" manually, it sometimes finds the network operators but always fails to connect to network. IMEI status OK in service mode. Settings > status shows: network: unknown > Service status: Out of service > mobile network state: disconnected. But the phone pops up with name of network operator of which ever Sim-card in insert. Very strange. Have been working on it for 3 days straight but unable to figure it out. Any help will be appreciated. Last edited by rafick; 02-20-2016 at 22:24.

02-22-2016, 12:08	#3 (permalink)
rafick Crazy Poster Join Date: Oct 2003 Posts: 56 Member: 40884 Status: Offline Thanks Meter: 4	Thanks for your reply/suggestions. I have now rooted the phone with 'CF auto root' and removed the Sim-card to do an unlock process again. All went well no problems, but the issue remains the same. When I manually select network it finds a few and when I select the correct one it says "the selected network in unavailable" "not registering on network" try later, nor matter which Sim-card/network I use (all working Sims). I get "emergency calls only" all the time. The strange thing is that is picks up the service provider on boot up and asks me to select the correct network. It also picks up the voicemail on one Sim-card but obviously I can't dial out. I have had this sort of problem before with other Samsung models (S4, S3... etc) and I used to flash a 'custom modem' file or use 'network repair' option or 'flash the QCN' files to resolve such problems. But with the Samsung S6 (SM-G920F) these options are not available in any of the repair boxes because I think it's a new qualcomm? I need something similar for the SM-G920F.

02-22-2016, 12:43	#4 (permalink)
Octopus box Product Supporter Join Date: Oct 2009 Location: Romania, Bucharest Posts: 99,841 Member: 1146942 Status: Offline Sonork: 100.1587278 Thanks Meter: 27,411	SM-G920F is Exynos-based phone and doesn't have a QCN. Please perform "Read Cert" operation, then try to writ a Cert file from the Support Area. Check whether phone obtains Network after writing of a Cert file.

02-22-2016, 20:02	#5 (permalink)
rafick Crazy Poster Join Date: Oct 2003 Posts: 56 Member: 40884 Status: Offline Thanks Meter: 4	Have just tried new certs but same results. The certs work fine on another S6 phone. I have installed "service mode" apps from app store and also installed 'Phone info' app. What I have noticed in the 'CSC CODE' section is that the Product code is blank (missing) others are all there - BTU, country, mobile operator etc Is this a clue? and how can i fix this? I can't seem to find any other faults. Thanks again for all your help.

02-23-2016, 11:11	#6 (permalink)
Octopus box Product Supporter Join Date: Oct 2009 Location: Romania, Bucharest Posts: 99,841 Member: 1146942 Status: Offline Sonork: 100.1587278 Thanks Meter: 27,411	In order to fix problem with CSC try to reflash the phone. You might need to root the phone, if it will have issues with turning on after writing of a firmware. We recommend to use CF Auto Root, to root SM-G920F.

03-03-2016, 19:02	#7 (permalink)
rafick Crazy Poster Join Date: Oct 2003 Posts: 56 Member: 40884 Status: Offline Thanks Meter: 4	I have tried to re-flash a number of different firmware files but the problem remains. I was able to temporary remove the "dm verity verification failed need to check DRK first" error message by flashing the 4 file firmware (5.1.1) and then it will get stuck on the Samsung logo, but again by flashing the same firmware but only the AP file below: (AP_G920FXXU3COI9_CL5816106_QB6438203_REV02_user_l ow_ship.tar) However, even with official firmware and not rooted the phone still has "emergency calls only" "No Network" error. The phone finds the network but no signal (cert is fine) I done a check using Phone info app and it shows this: Not sure if this information is helpful?

03-04-2016, 11:09	#8 (permalink)
Octopus box Product Supporter Join Date: Oct 2009 Location: Romania, Bucharest Posts: 99,841 Member: 1146942 Status: Offline Sonork: 100.1587278 Thanks Meter: 27,411	Unfortunately, if You have refurbished phone, we can't say what exactly can cause issues with Network without having the phone on hands.

03-22-2016, 22:14	#10 (permalink)
rafick Crazy Poster Join Date: Oct 2003 Posts: 56 Member: 40884 Status: Offline Thanks Meter: 4	Just an update: I decided to remove and replace the motherboard to reuse the 'brand new' screen and housing... and to my surprise I found that the motherboard was lightly water-damaged. I have cleaned the areas but have not tested the motherboard again. However, the question to my main problem "emergency calls only" "no service" has been answered. The baseband IC or other component[s] to do with signal maybe damaged. The Phone info app reported false information due to hardware problem. I hope this thread helps other people

03-23-2016, 00:13	#11 (permalink)
allumts No Life Poster Join Date: Apr 2011 Age: 58 Posts: 16,408 Member: 1564612 Status: Offline Thanks Meter: 12,343	Remember Always that Many of these APP also from Original PlayStore are developed by FAKE Peoples, if you will have read Last Info about 100th of APP from google Play Store "CRAMPED" you will have had most knowledge and NEVER use APP for try to repair one Phone like you model. Also Flash EFS from other Same phone isn't Good procedure....this is last attempt when have tryed in all mode of solve more advanced issue, not for Network where same Cert work fine in other same model. Is obvius that from you history is HW problem. I had one issue with one G925F accepting All fw , root, Kernel, Sboot, modem itc...but Always in Boot Loop, at the end after 4 days tryng via Sw have open phone and the problem was in the Flat of microusb connector, replaced this finish the Boot Loop and all other problem BR allumts