[General Questions and Answers] mattman1978:
Ok, I'm cross-posting this. I'm the author so yeah, whatever. Here Goes:

I've been studying this phone for a while and waiting for a root method. TWRP would be ideal, but it doesn't seem to be a priority for those with the talent to do so. In my research today, I may have stumbled upon what appears to be a means to root this phone (or any phone). Instead of looking around for "root", try instead to study and learn about Magisk. It seems to be the new preferred way to root newer devices. TWRP would make it easier, but there are instructions to use the stock firmware download and the Magisk app to achieve root for practically any device. Even if there is no TWRP available.

From what I can gather, Magisk modifies the stock Boot.img file. Once modified, it will allow you to switch root on and off much like we have in the past. It also has the added benefit of "hiding" from the OS, so the OS is not as likely to become aware of being rooted. It remains rooted even after Updates.

Have a look at this link for a better explanation and a basic how-to:

https://xdaforums.com/apps/magisk/how-to-install-magisc-twrp-locked-t3599926/page2

I post this so that the rest of you can try it as well, hopefully soon so we can compare notes and hopefully leverage each other's success. I'm downloading the Stock firmware now. This is NOT a "run a magic program and it roots my phone idiot-proof method", but it doesn't seem to be overly-complex either. Good luck and please report back.

CAUTION!!! Apparently, this phone may have 2 variants using the same model number! See links.

https://www.theandroidsoul.com/galaxy-j7-2017-release-date/

Here is the stock firmware. Again, two different variants. I would NOT assume they are cross-compatible.

Make SURE you get the right file for your device:

https://updato.com/firmware-archive-select-model?record=831FDD75692211E7963AFA163EE8F90B

Go into your "device info" and look at the build number. The two links in the above site show the build numbers. Make sure you get the right one! I happened to get the right one by dumb luck! I suggest anyone who is planning to root a phone have Odin + usb drivers installed and have the correct stock firmware on stand-by. These can be a great help, just in case. :)

No root yet, but I figured it out! I believe I can now root anytime I want.

Note, all steps below apply to the S727VL straight talk phone. As posted above, there are at least two distinct variants of this phone. It's possible that the roms and such are cross-compatible, but I would not bet on it. Go to "About device" and check the build number. Mine ends in AQB5.

I'm at the last step. All I have to do is use odin to flash my modified boot.img to the phone and it should be rooted. Reading and studying a bit more before I take the plunge. Here is the stock firmware in case you wish to follow along in this path:

https://updato.com/firmware-archive-select-model?q=S727VL&exact=1

Ok, I first turned on developer options.

Then, flip the OEM unlock switch to unlock the phone.

I have not encrypted anything on my phone. Not sure if it matters.

Download ODIN and usb drivers for samsung. Confirm it connects to the phone, but then close ODIN back out.

Confirm you have the right build number stock firmware. It'll give you a shot in case things go bad.

Now, extract the firmware.zip using 7-zip. Then, right click on each file individually and use 7-zip to extract them. You must use 7zip. Other compression tools don't seem to recognize it as an archive.

In any case, one of the files should have boot.img in it. I found boot.img in "AP_S727VLUDU1AQB5_CL10551307_QB12606263_REV00_use r_low_ship_MULTI_CERT.tar.md5"

I used the usb cable to transfer the boot.img file to my phone.

When using ODIN to flash or transferring files to and from the phone, use the usb cable that came with the phone. Cheap cables will lead to corrupt data and a brick. Trust me on this one!

Dowload the Magisk manager apk file and install it on the phone. It will NOT root the phone (yet anyway).

It will patch the boot.img file, which is critical to obtaining root by this method.

Using magisk manager, go to settings and change the "Patched Boot Output Format" to .img.tar This is required when using ODIN to flash samsung devices. :)

Click the "install" button and select "Patch boot Image File". Show it where the file is. I had to use OPEN Manager to find the file, but in any case, Magisk takes a few moments and then reports it's done.

Magisk produced a "patched_boot.img.tar" file. Supposed to be ready to flash using odin. It places it in "MagiskManager" folder on the phone.

This is where I am. I have stopped here. I believe I can put the phone in download mode and flash the modified boot.img.

Or do I put the updated version back into the same .tar.md5 file and then flash it?

Thoughts? Ideas?

The patched Boot.img file is a bit larger than the one I extracted. Apparently, odin is supposed to be able to flash this directly to the phone?

I'm very close, just not quite ready to pull the trigger. Anyone brave enough to throw caution to the wind and pull the trigger? Download ODIN and go for it. Of course, let us all know how it goes.

The patched boot.img file is 11.12mb. Original file was 10.86mb. Sounds reasonable...

I have put in a lot of time on this, I have done all the study and homework and even the prep work, but I'm hesitant to flash it. I'm going to read a bit more before I jump in.

NOTE: all of this assumes the download of the stock firmware is really the correct firmware for our phone and that the patch worked correctly. I didn't write Magisk and have never used it before. I'd feel better if someone else had already done this on this model.

Magisk info:

https://xdaforums.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445

https://xdaforums.com/apps/magisk/guide-magisk-troubleshooting-t3641417

So, here it is. Here is the boot.img from the stock firmware and the patched one as well. I offer them here to anyone willing to try it. I only ask that you report what happens. Everyone here wants to root, well here it is. Of course, I'm not liable for the use of this method or these files. I have NOT attempted it yet. Maybe in a few days.

Use at your own risk, please confirm build number and DO NOT use it if your phone does not match! By downloading these files, you agree to report the result back here on this thread, good or bad and you accept full responsibility.

Stock boot.img from the firmware download above.

https://www.dropbox.com/s/ws9q1dmpm7v7kx9/boot.img?dl=2

That is the STOCK, unedited boot.img that was extracted from the download:

(feel free to use magisk to modify it on your own phone if you wish). Do not use this boot.img on any other variant or any other model phone!

https://updato.com/firmware-archive-select-model?q=S727VL&exact=1

Build ending in AQB5 Confirm your build number as there are at least two variants of this phone!

I then used magisk on my phone to modify the boot.img

It produced this file:

https://www.dropbox.com/s/f60m5ek3q99dbuf/patched_boot.img.tar?dl=2

Again, use at your own risk and you MUST report results back to this thread if you use them. Good luck!!