[Samsung Galaxy J5 Guides, News, & Discussion] palmbeach05:
Straight from post #1 of that thread. Notice the starred parts below.

After updating my J5 2017 J530F to the latest Oreo 8.1 I was having trouble getting root and all things working again.

Hours of waiting for installs then something going wrong after applying the CF-Auto-root or trying to install Magisk or something and having to install again, Hours spent waiting..

Trying to install the auto-root would cause a verification error and force a system erase but not work again.

Thought i'd found the solution with the EDOs rom but then realised I had no bluetooth and had problems with mobile data.

After many efforts i found a way by simply installing the excellent Helios PRO kernel and manually installing Magisk after.

So I offer you the way i found to root my phone with Stock Oreo 8.1

A step by step breakdown of the method I used to fully root the fresh stock rom install.

First download the needed stuff

Latest Samsung Odin software. (3.13)

https://samsungodin.com/download

Download Link:

https://samsungodin.com/download/Odin3_v3.13.1.zip

USB Drivers.

https://samsungodin.com/SamsungUSBDriver/USB_Drivers_1.5.27.0.rar

New Oreo 8.1 Stock ROM

https://www.sammobile.com/firmwares/galaxy-j5/SM-J530F/BTU/

Download Link: https://www.sammobile.com/firmwares/galaxy-j5/SM-J530F/BTU/download/J530FXXU3BRL1/252803

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*************TWRP
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https://github.com/TwrpBuilder/andr...s/tag/TWRP-3.2.3-TwrpBuilder-2018-09-13_15-34

Download Link: https://github.com/TwrpBuilder/andr...2.3-TwrpBuilder-j5y17lte-2018-09-13_15-34.tar

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The Helios Pro Kernel

https://xdaforums.com/galaxy-j5/sam...velopment/kernel-refined-kernel-v1-0-t3675500

Note if you are not installing from fresh stock roms Helios kernel says...

If you have flashed Root through any means other than magisk, Please uninstall it (SuperSU>Full unroot)

Magisk , (All J5 roms kernels i installed that said they had magisk pre-installed never actually worked on my phone)

so I downloaded the files to manually install Magisk.

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

I used the main zip file and the manager apk

https://github.com/topjohnwu/Magisk/releases/download/v18.1/Magisk-v18.1.zip

https://github.com/topjohnwu/Magisk/releases/download/manager-v7.0.0/MagiskManager-v7.0.0.apk

Note: developer mode and OEM unlocking need to be enabled for most of these steps but many of the steps undo the settings so will need to be reapllied at various stages.

enable developer mode on phone by going to Settings/About phone/Software settings and keep pressing "Build Number" till developer mode activates then go back to main settings page and select "Developer Options" and make sure developer mode is enabled and USB debugging (i guess) and "OEM Unlock"

Method...

1. unpack Odin software and right click Launcher icon and select properties

Go to Compatibility settings and select Vista (service pack 2) compatibility.

Click okay and launch the Odin program.

2. Install stock ROM

Unpack the Oreo 8.1 files and use the buttons in Odin to load the BL , AP, CP and CSC files into each slot

Put phone into "Download Mode" by powering off and holding volume down - , home, and power buttons together till the screen pops up telling you to now press volume up to go to download mode.

Then plug in USB to computer.

Odin should report "Added" if you have correct samsung drivers on PC.

Then press "Start" in Odin.

Stock roms should all download to phone then it reboots.

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3. Flash TWRP

Boot up phone, log into an account and get it all running then enable developer mode again.

Once set copy the Helios pro kernel zip file and the magisk zip and apk files to the phones SD card.

Now power down the phone and put it in download mode again.

Load Odin again and now put only the TWRP installer .tar file into the "AP" slot then select the "Options" tab in Odin and uncheck the auto reboot option. then hit start and flash twrp.

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Load TWRP an install helios kernel

After flashing TWRP hold down the phones volume-down, home and power buttons and as soon as the screen goes blank immediately change volume down for volume up while still holding home and power.

then TWRP should load

Go to Wipe and select "Format Data" type yes to proceed , then back to wipe, select advanced wipe and wipe internal storage.

then back to TWRP main page and select "Install", select micro-sd card and point installer to the Helios Kernel zip file and install.

Install Magisk Manager app:

After booting up i still had no root so i installed the Magisk Manager apk using the "My files" app and launching it confirmed still no Magisk installed.

(I cannot recall if i had to go through the "Enable developer mode" again at this point but check if you need to or not)

Last Step, Manually Install Magisk.

Lastly I powered down the phone and held volume up, home and power key to launch TWRP

There i selected Install and installed the Magisk.zip file from SD card.

Finally the system booted, everything was working and i had root via an installed and working Magisk

Hope this helps someone..