[Sprint  Galaxy Note 4 Q&A, Help & Troubleshooting] XORr0:
Greets all,

Apologies in advance for the longer post.

TLDR: Writing the debrick-n910p.img image to SDcard using Windows (10 x86_64) for me caused my hard bricked SM-N910P / Sprint Samsung Galaxy Note 4 to endlessly boot-loop (displaying BOOT RECOVERY MODE / CHECK BOOT PARTITIONS.. / COPY FROM T-FLASH.. / BOOT RECOVERY / WRITE 188416 sectors / REBOOT). I found my solution for this issue to be that as long as I wrote the debrick-n910p.img image in Windows (10 x86_64), then booted into Linux and wiped the GPT data structures on the SDcard only to convert the SDcard to basic MBR (+DOS compatible flag), then created & formatted a single 32GB partition as FAT32, then and only then, write the debrick-n910p.img image file to the SDcard in this way, I was able to save my hard-bricked phone flawlessly!

I ran into the "mmc_read failed" issue that many posters to this site have experienced. I wanted to add the solution that worked for me along with the issues I ran into, as a reference for myself if I ever need it again in the future, and to pass on the information in the event others may find it helpful.

In all my trials and research I never found a point-by-point / exact instructions for the SM-N910P / Sprint Samsung Galaxy Note 4, nor anyone running into the same issue(s) that I did. that's what this post is => links to others solutions, my experience, and my solution for a hard-bricked SM-N910P / Sprint Samsung Galaxy Note 4.

SCENARIO: After ~6months of owning my phone I bought from craigslist it started experiencing random lagging, then random reboots, and ultimately the phone failed to boot into the OS one day. So I booted up TWRP, did a full-wipe and fresh OS load. after the OS flash (like I've done a million times, nothing different/strange) the device was set to reboot, then the screen went dark, and never came back on. just poof. it would flat-out not boot again; no LED during charging, nothing would happen when attempting to power on the phone, or any attempt to try booting recovery (Home+Vol-Up+Power) or to Odin/Kies download-mode (Home+Vol-Down+Power). To me the phone was dead, I considered it the "true brick". Yet, I wondered at the most curious thing that would happen when I connected the phone to my computer via the microUSB cable

without the battery

; I would hear the "new device attached" Windows chime, and Device Manager would list a new "Qualcomm HS-USB QDLoader 9008" device. otherwise, the phone remained dark, and completely void of any life.

At this point I started researching to purchase a replacement cellphone when a website caught my eye with the title "Qualcomm Snapdragon Unbrick Guide, Snapdragon’s are UNBRICKABLE".

I skimmed over the text, and began thinking it possible to revive my (broken?) phone - I just desired a straight-forward HOWTO describing the procedure how I could resurrect my phone, and I figured I would be on my way.

In the end, I found some promising posts, and the very SM-N910P debrick image itself (see below for links), but never found a step-by-step for my exact model of phone.

N910P Debrick Image + Useful Links

Mega Link to the N910P debrick image (128MB)

Samsung N910P Galaxy Note 4 Sprint USA Repair Firmware (N910PVPU4COG5_SPT4COG5_Sprint_USA_v5.1.1_Repair_Firmware.zip)

Win32DiskImager (Project Homepage) (v0.9 binary)

dd for windows

Galaxy Note 4 Unbrick/Debrick.img for N910G/F/T/W8 [unbrick] [unbrick image]

[*]- Inside, a reference For N910P refer this thread​

Galaxy Note 4 N910T FIXED HARD BRICKED

SM-N910P (US-Sprint) debrick.img

All instructions seemed to state I needed a 16GB or larger SDcard, so I went out and purchased a brand new 128GB MicroSDXC card, specifically Samsung MicroSDXC EVO Memory Card w/ Adapter 128GB (2017 Model) - Model: MB-MP128G / Model Code: MB-MP128GA/AM

The gist of all the reports on how to fix my issue was to write the N910P debrick image to a micro SDcard and magically the phone would come back to life. And so, I did just that. In my case using Windows 10 x86_64 - using the suggested applications to write the image to the SDcard: Win32DiskImager and/or dd for windows, then popping the SDcard into the "dead" phone, attaching the battery to the phone and pushing power - or one of the 3 finger salutes (recovery/download-mode) - then the magic would happen, the screen would show the following text:

BOOT RECOVERY MODE
CHECK BOOT PARTITIONS..
COPY FROM T-FLASH..
BOOT RECOVERY
WRITE 188416 sectors
REBOOT

But, unfortunately for me, that is all it would do, I would keep seeing that text over and over... If I let the "COPY FROM T-FLASH.." appear then press one of the 3 finger salutes (recovery -or- download-mode), the phone would just reboot before it displayed the rest, and continue back in it's loop:

BOOT RECOVERY MODE
CHECK BOOT PARTITIONS..
COPY FROM T-FLASH..
BOOT RECOVERY
WRITE 188416 sectors
REBOOT

This just kept occurring over, and over with infinite reboots. Yet, ALL the documentation said it would ultimately boot into download-mode, I just had to "put it in the freezer to let the phone cool" (never mind that the phone wasn't hot AT ALL) for an hour or something similar?? All my searching found nobody else with this issue (at least no one reporting it). So I am reporting it and also reporting how I fixed my sorry state of affairs.

As I noted above, I was using Windows 10 x86_64 as the OS and Win32DiskImager, as well as dd for windows, to write the debrick image to the SDcard up to this point. This was my process:

:: Windows 10 ::

place SDCARD in drive

format the SDCARD (drive d:/f:, whichever) through Windows Explorer (explorer.exe) via RIGHT-CLICK on drive -> Format ...

capacity 119GB / Filesystem: exFAT / Allocation Size: drop-down = Default Allocatio-- n Size

CHECK Quick Format

click Start button

click OK

click OK when finished

click Close button

in Windows Explorer (explorer.exe), RIGHT-CLICK on SDCARD drive -> Eject

eject SDCARD from computer

- EITHER Win32DiskImager OR dd for windows, only do 1.

:: Win32DiskImager ::

run Win32DiskImager as Administrator

DEVICE = drive of the SDCARD (D:/F:, whichever)

IMAGE FILE = click FOLDER icon, select "debrick-n910p.img"

click WRITE button

click OK

at Write Successful = click OK

more then likely (win10) a ****-ton of Explorer screens pop up, with errors like "You need to format the disk in Drive ? before you can use it" pops up

IGNORE ALL THIS, ALT-F4 to close ALL the pop-ups and errors

OR just REBOOT, as at this point we are done

Shutdown Windows (10) -> REBOOT

:: dd for windows ::

open "cmd" as Administrator

dd --list

dd if=debrick-n910p.img of=\\.\Volume{3fde94fa-d22d-11e7-b791-806e6f6e6963} bs=1M

Once the debrick-n910p.img file is finished being written to the SDcard, 27 partitions (what appears to be mostly duplicate) will show up and all drive letters will get filled, being displayed as mostly unreadable, that is just the nature of what the debrick image is.

My Solution to this situation was as follows:

:: LINUX ::

boot linux from USB -or- CD (I booted a handy USB stick with Qubes OS v4-rc3, choose Troubleshooting -> Rescue a Qubes System)

upon boot, choose "3" to be dropped to shell

mount windows folder that holds the debrick N910P image = mount /dev/sda2 /mnt/sysimage

place SDCARD in drive

fdisk -l << make sure your SDcard shows up (/dev/mmcblk0) is there

cgdisk /dev/mmcblk0

delete ALL paritions (using "d" on each highlighted partition)

"New"

Fist sector = hit ENTER (choose default = 2048 for me)

Size in sectors = 32G

Hex code = 0700 (Microsoft basic data)

Partition name = hit ENTER

"Write"

type "yes"

"Quit"

gdisk /dev/mmcblk0

should display = "Found valid GPT with protective MBR; using GPT"

"x" (extra functionality (experts only))

"z" (zap (destroy) GPT data structures and exit)

"Y" (Yes to continue)

"N" (blank out MBR)

fdisk /dev/mmcblk0

"p" (print parition table)

"c" (toggle dos compatibility flag)

should show DOS COMPATABILITY FLAG SET (DEPRICATED)

"d" (delete partition)

MAKE SURE NO PARTITIONS EXIST!

"n" (new partition)

"p" (primary)

hit ENTER (default = "1")

hit ENTER (first sector, my default was 63)

"+32G" (last sector, this creates 32GB partition)

"a" (toggle bootable flag, should show "the bootable flag on partition 1 is enabled now")

"t" (partition type)

"c" (W95 FAT32 (LBA))

"w" (write table to disk and exit)

Format the new partition, FAT32

mkfs.fat -F 32 /dev/mmcblk0p1

Goto the folder containing the debrick N910P image

cd /mnt/sysimage/Users/$USER/Downloads/SM-N910P-trltespr

dd if=debrick-n910p.img of=/dev/mmcblk0 bs=1M

sync

Eject sdcard and place in your Note 4 phone

This time, when I put the battery in the phone, I got the same text as before:

BOOT RECOVERY MODE
CHECK BOOT PARTITIONS..
COPY FROM T-FLASH..
BOOT RECOVERY
WRITE 188416 sectors
REBOOT

And then, it did a REAL reboot, and went directly to download-mode!

I tested this multiple times - as long as I wrote the debrick image in Win10, and then erased the SDcard and formatted it as Fat32 without using GPT just a basic MBR, and wrote the debrick image that way in linux it worked flawlessly!

let it boot, then do it's reboot

should be able to go into RECOVERY = Home+Vol-Down+Power !!!

:: Boot Windows ::

unzip "N910PVPU4COG5_SPT4COG5_Sprint_USA_v5.1.1_Repair_Firmware.zip"

run Odin3 3.09

click PIT button -> select "TRLTE_USA_SPR.pit" -> click OPEN

click AP button -> select "ALL_SPT_N910PVPU4COG5_N910PSPT4COG5_CL5303209_QB5691107_REV00_user_low_ship_MULTI_CERT.tar.md5" -> click OPEN

phone should be in DOWNLOAD mode (home+vol-down+power -> UP to continue) and connected via microUSB, Odin3 should be detecting it with a BLUE ID:COM lit up on top-left

click START button in Odin3

when finished it will reboot, and all should be well

- One last note, about the "mmc read fail" error, I took this gentleman's advice:

And am currently running Wake Lock - PowerManager from Google Play as suggested, just to be safe - and so far, I have not YET had to deal with that horrid business again (so far, fingers crossed).

And there ye have it, that is my story, my tribulations, and my fix. Thank you to all who came before me, and for everyone's good advice = Good luck to all, and have a great rest of 2017.