Galaxy S6 cycles through startup, won’t boot to normal mode, other issues

Welcome to another #GalaxyS6 troubleshooting episode! Our post for today addresses the common experience of a lot of S6 users so we hope this material will be of help.

If you are looking for solutions to your own #Android issue, you can contact us by using the link provided at the bottom of this page.

When describing your issue, please be as detailed as possible so we can easily pinpoint a relevant solution. If you can, kindly include the exact error messages you are getting to give us an idea where to start. If you have already tried some troubleshooting steps before emailing us, make sure to mention them so we can skip them in our answers.

Below are specific topics we’re bringing for you today:

Problem 1: Galaxy S6 cycles through startup, won’t boot to normal mode

Verizon phone used on AT&T network. System cycles through Startup. Has integrated battery so can’t just pull it for soft reset. Tried several options listed on this site for starting in safe mode. Won’t go to safe mode. Only to ANDROID RECOVERY. Tried the Wipe Cache partition, no change. When I try to start in Safe Mode, shows light blue screen and android guy saying, Applying updates. But then goes to the android guy fallen down with a caution triangle above his head. Then goes to Android Recovery screen. Info from that screen ANDROID RECOVERY MMB29K.920F0VVRS4CQA3 user/release-keys Use Volume up/down and power. Options are: Reboot System Now (goes into start up cycle-Gets to Verizon screen before it starts over) Reboot to Bootloader (didn’t use that option, a quick search on the net says that is a no-no) Apply Update from AOB (says to send filename…no clue how or what to do with that) Apply Update from SD Card (researched something about downloading ODIN via Sammobile, but many still have the same problem.) Wipe Date/Factory reset (Have not tried that-hoping it is a last resort although I have seen others say they still have the same problem.) Wipe Cache Partition (tried it via Droid Guy advice…to no avail.) Mount  /System (Have not tried it….no clue what it does.) View recovery logs. (Shows a listing of each time it cycled through start up various filename endings) Power Off (it does indeed power off.)  Bottom of that screen: Supported API: 3 #Manual Mode# — Applying Multi-CSC… Applied the CC code:VZW Successfully applied multi-CSC. I am optimistic that there is a solution which will prevent the use of a factory reset. 🙂 Appreciate any assistance you might provide. When it started, it was plugged in and charging and I had used it with no problems. Purchased as factory refurbished phone via Amazon in April of this year. — Peggy S

Solution: Hi Peggy. An issue like yours is usually the result of an update or flashing gone wrong. Since you did not indicate what you did differently that may have led to the issue at all, we assume you tried any of the two. If that’s the case, either a factory reset or reflashing of the bootloader back to stock may help. A third possible reason for this problem can be hardware in nature, usually due to a corrupted memory, also known as the eMMC NAND chip. If any of the software solutions such as factory reset or reflashing of the bootloader won’t help, you’re out of luck. You must either have the motherboard replaced, or simply get another phone.

As far as software troubleshooting are concerned, below are the logical steps that must be done:

  1. soft reset
  2. cache partition wipe
  3. restart to safe mode (to see if a third party app is responsible)
  4. factory reset
  5. flashing of bootloader and/or firmware

For reference, these are the steps on how to reflash a Samsung Galaxy S device’s bootloader. Your particular phone model may have a slightly different flashing procedure than the one below.

  1. Look for the correct firmware for your phone model and download it. Make sure that you select the right one. It should be the same exact firmware that ran previously on your device. We assume that you list down the firmware version somewhere. If you did not take note of it before, there’s a chance that you may pick the wrong one. As you may know now, using an incorrect firmware can cause complications so good luck with that.
  2. Let’s now say that you have identified the correct firmware. You then want to download it to your computer. The firmware file should have a bunch of files in it like AP_, BL_, CSC_, etc.
  3. Look for the file that starts with a label BL; this should be the corresponding bootloader file for this firmware. Once you’ve identified the bootloader file, copy it to your computer’s desktop or to any other folder that you can easily access.
  4. Proceed with the rest of the flashing procedure using the Odin program.
  5. In Odin, click on the BL tab and make sure to use the bootloader file you’ve identified earlier.
  6. Now, make sure that the “Device Added” status and its “ID:COM box” has turned blue before hitting the START button. This will initiate the flashing of your phone’s bootloader.
  7. Restart the phone once the procedure is finished.

Problem 2: Galaxy S6 screen won’t turn on after accidental drop

Dropped the phone on carpet at the height of door handle with case on screen intact. Not a screen problem but the phone is absolutely dead — won’t charge or do anything when I try to reboot it in safe mode with power button and volume keys home button. I tried all of that so many times but it still won’t turn on. The only lead I have so far is a clicking sound if makes when I shake the phone forward and backward. something inside the phone shaking perhaps the battery. it sounds big enough to be the battery not too sure and the sound is coming from the top part of the phone. Leaving on a trip soon please get back to me soon. — Issay

Solution: Hi Issay. There are three things that you must check to know where the problem lies:

  • verify if all accessories like USB cable/charging cable, charger/adapter, external case, and power outlet are all working
  • determine if the phone is simply not charging, leaving the battery out of power at this time
  • troubleshoot the screen

Sometimes, a bad accessory can make it appear like the phone is defective since it won’t power on all of a sudden. Make sure that you try another set of known working accessories from another Samsung device to see if the phone has simply ran out of power due to a defective charger or charging cable.

If the phone does not make any sound notification, vibrate during restart, or show any LED light while charging, it must be totally dead. This means that no power reaches the motherboard causing total failure. This can be due to bad battery, a broken motherboard, or some other unknown hardware failure due to the unnecessary shock from the drop. In this case, you’ll need to let a professional check the device so the hardware can be examined.

If the phone still charges, make a sound notification, or show LED light, the problem must be isolated to the screen only. If you don’t know how to replace or fix the screen, you must let a professional do it for you.

Problem 3: Galaxy S6 stuck in Download Mode

Black Screen on S6 (SM-G920F). Literally the only thing I can do with it are:


  • Press Power, Home and Volume Down Buttons
  • Press Vol down to reboot
  • Samsung black splash screen – Blue Android screen that says ‘Installing updates’
  • Returns to black screen or off


I’ve tried Dr. Phone and Android Recovery Software both of which unsuccessful.  Please help! Thanks in advance.  — Jonathan Carrasco

Solution: Hi Jonathan. Please refer to our suggestions for Peggy above. Before you try to reflash the bootloader though, make sure that you also try to boot to Recovery Mode so you can do the twin solutions of cache partition wipe and factory reset. If the phone won’t restart to Recovery Mode at all, that’s the time that you see if reflashing the bootloader will help.

Below are the steps on how to restart the phone to Recovery Mode:

  1. Charge the phone for at least 30 minutes.
  2. Press and then hold the Home and Volume UP keys, then press and hold the Power key.
  3. When the Samsung Galaxy logo shows on the screen, release the Power key but continue holding the Home and Volume Up keys.
  4. When the Android logo shows, you may release both keys and leave the phone be for about 30 to 60 seconds.
  5. You can either wipe the cache partition or do a factory reset when in this mode. Try to wipe the cache partition first. If that won’t work, bring the phone back to Recovery menu and select “Yes — delete all user data” to factory reset the device.

Software solutions like the one’s detailed in this article are only meant to fix issues due to software faults. If none of the steps above won’t resolve your issue at all, have the phone repaired or replaced.


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