Customizing your Verizon Galaxy S4 - what's possible and what's not

The number one reason people brick their Verizon Galaxy S4 phones is due to attempts to flash recovery using Goo Manager, dd, and other tools without understanding when those will or won't work. The Verizon S4 is very locked down, and will reject such attempts in most cases.

The only Verizon Galaxy S4 release that permits a custom recovery is a phone with the original MDK bootloader. Not checking first to tell what's installed before flashing will often break your phone.

1. What releases are there, and how can you tell what you have?

There are currently 7 different releases of the firmware for the I545.

• VRUAMDK (Usually called just "MDK")
• VRUAME7 ("ME7")
• VRUDMI1 ("MI1")
• VRUEMJ7 ("MJ7")
• VRUEMK2 ("MK2")
• VRUFNC2 ("NC2")
• VRUFNC5 ("NC5")

There's another release that was apparently a leak or limited release, MG7.

You've got to know what bootloader and firmware you have installed before you do anything. The bootloader is the critical thing, but unless you're using a MDK bootloader, chances are that the bootloader on your phone is the same as the build version. To figure out what you're running, use the "Settings", "More", "About phone" menu. In most cases, the "Baseband version" displayed and the "Build number" will be the same, which tells you what build you're on. The best way to tell what bootloader you have is to install an app - "Phone INFO *Samsung*" and "Phone info" will both tell you what build and bootloader you have.

The "Developer Edition" devices have "I545OYUA" build numbers versus the consumer versions, which start with I545VR.

Once you're on a particular build, it is not possible to downgrade to an earlier release. The single exception to this is that you can flash MJ7 over MK2, but that's it.
If you're past MDK, you can't bypass the bootloader until an exploit is found.

If you start flashing things without verifying that it's for the release on YOUR phone, you risk bricking it. There's dozens of youtube videos telling you how to flash custom recovery on your phone that WILL NOT WORK unless you're on the MDK bootloader. Be sure to comment in the youtube thread after they assist you with bricking your phone.

If you need to tell for sure what bootloader you're on, you can use applications like "Android System Info" (Open the "System" tab and the "Buildinfos" and look for Bootloader), or from a shell by using the command "getprop ro.bootloader". Use either adb shell or the "Terminal Emulator" app to do that.

2. What can you do with your phone?

Rooting:

For MDK, root using this link. or this link.
For ME7, root using this link.
For MI1, root using this link.
For MJ7 and MK2, root using this link.
For NC2 and NC5, you can't currrently root unless you downgrade the baseband to MK2.

If you want to install a custom recovery, you MUST have the MDK bootloader. Follow the MDK link above.

If the bootloader isn't "I545VRUAMDK" you have a locked bootloader and can only use Safestrap to install custom ROMs. Custom recovery is not possible. Attempts to install custom recovery will soft-brick your phone and require you to re-flash a stock ROM.

Information on Safestrap is available in this thread.

Recover by re-flashing stock

For MDK, Follow this link.
For ME7,Follow this link.
For MI1, Follow this link.
For MJ7, there's a no-wipe and a full wipe image.
For MK2, Follow this link.

Flash new Modems
The firmware that runs the phone's radios, which allows you to connect to the networks (CDMA, LTE, WiFi, Bluetooth) can be updated independently of the bootloader. Flashing the MJ7 modem can get you new LTE bands, for example. Read here for information on available modems.

3. What to avoid

Every carrier's version of the Galaxy S4 is different. Things that work for the Sprint, AT&T, T-Mobile, and other carriers phones may not work on the Verizon version and can lead to bricking your phone. Don't do things just because it works on the T-mo, AT&T, or sprint phones unless you don't care if your phone is rendered useless.

Regardless of what you read, recommendations to use Goo Manager to flash custom recovery will not work and will soft brick your phone unless you're running the MDK bootloader. Don't do that.

If you manage to do the wrong thing and soft-brick your phone, search the Android Development forum for a factory image that can be flashed to recover it based on what baseband you started with.

For example, this image for MJ7 (Android 4.3).

I posted this hoping it would become a sticky.
Moderators: any chance? Or is this unacceptable since it's not a question?

k1mu said:

I posted this hoping it would become a sticky.
Moderators: any chance? Or is this unacceptable since it's not a question?

Click to expand...

Click to collapse

this really needs to be a sticky as we all know how many aren't taking the time to more than a cursory check in these threads

---------- Post added at 06:16 AM ---------- Previous post was at 06:09 AM ----------

k1mu said:

The number one reason people brick their Verizon Galaxy S4 phones is due to attempts to flash recovery using Goo Manager, dd, and other tools without understanding when those will or won't work. The Verizon S4 is very locked down, and will reject such attempts in most cases.

The only Verizon Galaxy S4 release that permits a custom recovery is the original MDK baseband. Not checking first before flashing will often break your phone.

If you need to know what baseband you're on, use "Settings", "More", "About phone" and scroll down to the "Baseband Version".

Every carrier's version of the Galaxy S4 is different. Things that work for the Sprint, AT&T, T-Mobile, and other carriers phones may not work on the Verizon version and can lead to bricking your phone. Don't do things just because it works on the T-mo, AT&T, or sprint phones unless you don't care if your phone is rendered useless.

Regardless of what you read, recommendations to use Goo Manager to flash custom recoverywill not work and will soft brick your phone unless you're on the MDK baseband. Don't do that.

If you manage to do the wrong thing and soft-brick your phone, search the Android Development forum for a factory image that can be flashed to recover it based on what baseband you started with.

For example, this image for MJ7 (Android 4.3).

Click to expand...

Click to collapse

k1mu, I also created a step by step guide (with links) that walks you thru the entire process of going from ME7/MI1 to MJ7 by flashing the wipe tar image of MJ7, installing your saferoot, safestrap and HD11

http://xdaforums.com/showthread.php?t=2579278

I was feeling pretty bad for all the people that were messing up their phone becasue od not understanding the entire process.

Some clarification on OP for those with Dev Edition and more What’s possible Q's

Thank you, to k1mu and other contributors. It was an excellent idea especially for those starting out. I’ve found a couple of threads dedicated to the dev. edition but it

I have the Galaxy S4 (SCH-I545) - Verizon, Developer Edition.

Build number:
JDQ39.I545OYUAMDK
Baseband version: I545OYUAMDK
Android Version 4.2.2

The OP stresses the importance of being mindful of your firmware version when following threads/guides so as not to brick one’s phone. I understand that shorthands like “MDK” are commonly used, but I’m not sure if these shorthands necessarily have wider implications of “any build number ending in MDK”. I’m not sure if all firmwares ending in “MDK” may be treated the same or if it refers specifically to the seemingly more popular VRUAMDK version. I couldn’t help but notice that mine says “OY” instead of “VR” (maybe it’s a dev. edition thing).

[ANSWERED] 1. Is this something I need to be concerned about? That is, is it okay to follow threads/guides for “MDK” just the same as if I have VRUAMDK? When people say MDK does it encompass all firmware that ends in MDK?
"The DevS4 came originally with I545OYUAMDK. The retail S4 came with I545VRUAMDK. The only difference is that the DevS4 has a different ABOOT partition which allows for the unlocking." "The DevS4's are now sold with I545OYUEMJ7"
- So apparently the OY means that the bootloaders are unlockable (Dev. edition). This will be irreversibly be changed with firmware update (can no longer be unlocked).

2. Should I also be wary of the first part of the Build number/firmware? JDQ39. ? Is it safe to follow directions with different numbers (first part)? While I’m at it, how about the Android Version is that important when it comes to do’s and don’t’s and not bricking my phone?

[answered] 3. Is there a way to turn off over-the-air (OTA) updates? I felt like this question was relevant to this thread as it can change firmware versions which has implications for what’s possible and what is not.
- "If you get a file explorer like Root Explorer, you can rename the sdm.apk to sdm.apk.bak and it should stop it."

4. I haven’t activated my phone yet. Does it matter if I unlock/root my phone before or after activating service?

I just want some confirmation/verification on these things so I don’t brick my phone. Also, I’m more familiar with using custom recovery/TWRP from my other android device whereas I’ve never heard of SS. The OP is pretty clear that firmware updates are irreversible. As such, it would be nice to know how to retain my ghetto, less up-to-date firmware.

I would much appreciate it if the more knowledgeable folks on this forum would chime in. In the meantime I’ll do more searching and sifting through threads. I’ll post/update if and when I find answers. Hopefully, it would be of use to others out there with dev. edition.

eternally grateful,
ns

decaturbob said:

many guides and threads that everyone needs to read to understand the process of what they are getting into before they brick their phone and it costs themselves some money.

Click to expand...

Click to collapse

The Bieeeeb has been getting into a lot of trouble lately, not easy I'm sure to keep up on this android stuff while racing Lambos high and drunk.

Sent from my SCH-I545 using XDA Premium 4 mobile app