This is a fix for dropping signal, dropped calls, LTE issues, and any other cell related issues you may be having. I am not promising a miracle fix, but this should alleviate most, if not all the problems you are having. If you still are having major problems I would recommend you RMA the device after returning to stock.
I want to start off by saying you have to be unlocked. If you are not, then this will not work for you. I have included instructions on how to do this for your convenience.
This is my first time doing this, so please speak up if you spot a mistake or have suggestions for improvements.
DISCLAIMER: I am NOT responsible for your actions. I posted this as a guide, if you brick or blow up your phone do not come to me with blame. I will help you as best I can if you run into trouble but please read the instructions carefully before proceeding
Please read through the instructions carefully at least twice, especially if you don't know what you are doing. While its mostly safe (as it's a Nexus device), if you miss a step you will regret it later on. Trust me, I've been there before. It's not pretty.
Unlock your device:
0. Backup. You can use G Cloud Backup or any other app/method you want to use. Everything not backed up will be deleted. You are going to factory reset.
1. Install ADB and drivers. Easiest way to do this is to use this. If that doesn't work uninstall everything it installs and manually download/install this and this. If that doesn't work, use Google
.
2. Extract the SDK you downloaded to your desktop and navigate to "sdk".
3. Press and hold shift and right click on platform-tools. Click "Open Command Prompt Here".
4. Boot the Nexus 5 into the bootloader (Turn the phone off and press/hold Power + Volume Down).
5. Connect the Nexus 5 to your computer.
6. Type in "adb.exe" in the command prompt. It should return a whole lot of crap. This means adb is working correctly.
7. Type in "fastboot devices". This should return a lot of numbers and letters followed by "fastboot". -If it is blank or returns an error reinstall and check your drivers!!! Do NOT proceed until you get the numbers and letters which signify the device's fastboot ID. Reopening the command prompt may work.
8. Type "fastboot oem unlock".
9. Hit "Yes" on the phone. Your phone will factory reset, make sure you are backed up.
10. Watch the phone. It should be doing stuff at the bottom underneath the red text. Once that is done, wait 1 minute and type "fastboot reboot". This is extremely important, make sure you do this.
11. Your phone will reboot to the Android recovery robot wiggling his ears. Wait until the phone fully reboots. This can take up to 15 minutes. Be patient.
12. Congratulations, you are unlocked when your phone boots. You can make sure by watching the phone when it boots. Underneath the Google logo it should show an unlocked lock.
Installing a Custom Recovery:
1. Boot into bootloader (Power + Volume Down)
2. Plug phone into your computer.
3. Download the recovery image on this XDA page under downloads. I highly recommend you download CWM, but TWRP works just as well.
4. Move the download to your platform-tools folder.
5. Press and hold shift. Right click the platform-tools folder and click "Open Command Prompt Here".
6. Type in "adb.exe" to ensure working adb. This is not required, but I like to be overcautious.
7. Type in "fastboot devices". Again, make sure the bunch of letters/numbers comes up followed by "fastboot". -If it is blank or returns an error reinstall and check your drivers!!! Do NOT proceed until you get the numbers and letters which signify the device's fastboot ID. Reopening the command prompt may work.
8. Type in "fastboot flash recovery XYZ.img. Replace XYZ with the filename of the recovery image (example: "fastboot flash recovery CWM1.5.img"). This command can take some time. Be patient.
9. Once the command is finished close the command prompt window.
10. In the Bootloader, using the volume keys find "Restart Bootloader". Hit the power button to select. Once the bootloader reboots find "Recovery Mode" and select it.
11. Your custom recovery will boot. In CWM recovery go into Backup/Restore using the volume keys.
12. Select it with the power button.
13. Select "backup" with the power button. This ensures you have a fresh, working backup in case something goes wrong.
14. Go to reboot phone. If the recovery warns you about something just hit yes. Seems like a common bug with recent versions of CWM.
15. When your phone reboots head back to the recovery through the bootloader to ensure the recovery stuck. If recovery boots to an Android with an exclamation point above him you will have to repeat the recovery section.
Flashing new Modem:
This is the way we are going to fix your phone's dropped signal, etc. To back up the EFS partition, you need to install a custom recovery. This is very important. If you ruin your EFS partition you are royally screwed if you don't have a backup. This is unique to each device. Please look above for instructions on how to install a custom recovery.
We will be flashing a new modem. In Laymen's terms the modem is the software that controls your cell's hardware - your signal is all regulated by this. You will be downloading all of the files from here.
Pick any of the modems. Use trial and error to see which works best for you. Some will work better for others due to carrier and location. You can use 821's files on the 820 and vice versa. Google made it easy for us.
0. Backup EFS in either CWM or TWRP by flashing provided ZIP. Copy the folder (.zip directory - don't unzip) to a safe place on your computer. You will need this if your phone's EFS partition gets corrupted.
1. Boot into the bootloader. (device off - Power + Volume Down)
2. Copy the image file you downloaded into the SDK's platform-tools folder. Do not download the .zip - those are for custom recoveries. Doing it via Fastboot is much safer and Fastboot works with the image files. The image files will be larger and will be terminated with a .img file extension.
3. Hold shift and right click on the platform-tools folder.
4. Click on "Open Command Prompt Here".
5. Type "fastboot devices". -If it is blank or returns an error reinstall and check your drivers!!! Do NOT proceed until you get the numbers and letters which signify the device's fastboot ID. Reopening the command prompt may work.
6. Type "fastboot flash radio XYZ.img". Replace XYZ with modem's name (example: "flash radio IAMAMODEM.17.img").
7. Type "fastboot reboot".
8. The phone should reboot with your new modem. Enjoy!
I want to start off by saying you have to be unlocked. If you are not, then this will not work for you. I have included instructions on how to do this for your convenience.
This is my first time doing this, so please speak up if you spot a mistake or have suggestions for improvements.
DISCLAIMER: I am NOT responsible for your actions. I posted this as a guide, if you brick or blow up your phone do not come to me with blame. I will help you as best I can if you run into trouble but please read the instructions carefully before proceeding
Please read through the instructions carefully at least twice, especially if you don't know what you are doing. While its mostly safe (as it's a Nexus device), if you miss a step you will regret it later on. Trust me, I've been there before. It's not pretty.
Unlock your device:
0. Backup. You can use G Cloud Backup or any other app/method you want to use. Everything not backed up will be deleted. You are going to factory reset.
1. Install ADB and drivers. Easiest way to do this is to use this. If that doesn't work uninstall everything it installs and manually download/install this and this. If that doesn't work, use Google
.2. Extract the SDK you downloaded to your desktop and navigate to "sdk".
3. Press and hold shift and right click on platform-tools. Click "Open Command Prompt Here".
4. Boot the Nexus 5 into the bootloader (Turn the phone off and press/hold Power + Volume Down).
5. Connect the Nexus 5 to your computer.
6. Type in "adb.exe" in the command prompt. It should return a whole lot of crap. This means adb is working correctly.
7. Type in "fastboot devices". This should return a lot of numbers and letters followed by "fastboot". -If it is blank or returns an error reinstall and check your drivers!!! Do NOT proceed until you get the numbers and letters which signify the device's fastboot ID. Reopening the command prompt may work.
8. Type "fastboot oem unlock".
9. Hit "Yes" on the phone. Your phone will factory reset, make sure you are backed up.
10. Watch the phone. It should be doing stuff at the bottom underneath the red text. Once that is done, wait 1 minute and type "fastboot reboot". This is extremely important, make sure you do this.
11. Your phone will reboot to the Android recovery robot wiggling his ears. Wait until the phone fully reboots. This can take up to 15 minutes. Be patient.
12. Congratulations, you are unlocked when your phone boots. You can make sure by watching the phone when it boots. Underneath the Google logo it should show an unlocked lock.
Installing a Custom Recovery:
1. Boot into bootloader (Power + Volume Down)
2. Plug phone into your computer.
3. Download the recovery image on this XDA page under downloads. I highly recommend you download CWM, but TWRP works just as well.
4. Move the download to your platform-tools folder.
5. Press and hold shift. Right click the platform-tools folder and click "Open Command Prompt Here".
6. Type in "adb.exe" to ensure working adb. This is not required, but I like to be overcautious.
7. Type in "fastboot devices". Again, make sure the bunch of letters/numbers comes up followed by "fastboot". -If it is blank or returns an error reinstall and check your drivers!!! Do NOT proceed until you get the numbers and letters which signify the device's fastboot ID. Reopening the command prompt may work.
8. Type in "fastboot flash recovery XYZ.img. Replace XYZ with the filename of the recovery image (example: "fastboot flash recovery CWM1.5.img"). This command can take some time. Be patient.
9. Once the command is finished close the command prompt window.
10. In the Bootloader, using the volume keys find "Restart Bootloader". Hit the power button to select. Once the bootloader reboots find "Recovery Mode" and select it.
11. Your custom recovery will boot. In CWM recovery go into Backup/Restore using the volume keys.
12. Select it with the power button.
13. Select "backup" with the power button. This ensures you have a fresh, working backup in case something goes wrong.
14. Go to reboot phone. If the recovery warns you about something just hit yes. Seems like a common bug with recent versions of CWM.
15. When your phone reboots head back to the recovery through the bootloader to ensure the recovery stuck. If recovery boots to an Android with an exclamation point above him you will have to repeat the recovery section.
Flashing new Modem:
This is the way we are going to fix your phone's dropped signal, etc. To back up the EFS partition, you need to install a custom recovery. This is very important. If you ruin your EFS partition you are royally screwed if you don't have a backup. This is unique to each device. Please look above for instructions on how to install a custom recovery.
We will be flashing a new modem. In Laymen's terms the modem is the software that controls your cell's hardware - your signal is all regulated by this. You will be downloading all of the files from here.
Pick any of the modems. Use trial and error to see which works best for you. Some will work better for others due to carrier and location. You can use 821's files on the 820 and vice versa. Google made it easy for us.
0. Backup EFS in either CWM or TWRP by flashing provided ZIP. Copy the folder (.zip directory - don't unzip) to a safe place on your computer. You will need this if your phone's EFS partition gets corrupted.
1. Boot into the bootloader. (device off - Power + Volume Down)
2. Copy the image file you downloaded into the SDK's platform-tools folder. Do not download the .zip - those are for custom recoveries. Doing it via Fastboot is much safer and Fastboot works with the image files. The image files will be larger and will be terminated with a .img file extension.
3. Hold shift and right click on the platform-tools folder.
4. Click on "Open Command Prompt Here".
5. Type "fastboot devices". -If it is blank or returns an error reinstall and check your drivers!!! Do NOT proceed until you get the numbers and letters which signify the device's fastboot ID. Reopening the command prompt may work.
6. Type "fastboot flash radio XYZ.img". Replace XYZ with modem's name (example: "flash radio IAMAMODEM.17.img").
7. Type "fastboot reboot".
8. The phone should reboot with your new modem. Enjoy!
Last edited:
. Plus finals are coming up in the next two weeks. 
. Do you want a video of the entire process? Or just the radio? 
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