[Remix OS for PC] electrikjesus:
Using Jide's REMOUNT_RW=1 method to achieve R/W & true root

Both of these methods assume you have used Jide's latest Official Installer for either 32bit or x64 RemixOS 3.x install. This process will extract the system.sfs file, taking up an additional 2.6 gb (something around there), so make sure you have plenty of space for this.

NOTE: For OTA updates, please see the OTA Updates section below.

For RemixOS legacy boot installs (32 & 64 bit) using MBR from Jide's Installer (NON-UEFI)

You will want to make sure you can view hidden and system files in Explorer options (if you need to , google it), Once you do that, travel to C:\RemixOS (or where yo installed it) and using Notepad++ or your code editor of choice, find and open the menu.lst file. Then add a second entry containing the REMOUNT_RW=1 entry like you see below:

default 0
timeout 10

title Resident mode - All your data and apps are saved
find --set-root /RemixOS/kernel
kernel /RemixOS/kernel root=/dev/ram0 androidboot.hardware=remix_x86 androidboot.selinux=permissive quiet SERIAL=random logo.showlogo=1 SRC=RemixOS/ DATA= CREATE_DATA_IMG=1
initrd /RemixOS/initrd.img
boot

title Resident mode - RW enabled
find --set-root /RemixOS/kernel
kernel /RemixOS/kernel root=/dev/ram0 androidboot.hardware=remix_x86 androidboot.selinux=permissive quiet SERIAL=random logo.showlogo=1 SRC=RemixOS/ REMOUNT_RW=1 DATA= CREATE_DATA_IMG=1
initrd /RemixOS/initrd.img
boot

Once you are done, you can reboot, and choose the entry you added. It will then extract the system.sfs file to a system_dev.img, and mount it as RW for you. Once booted, you can update SuperSU from Play store and enjoy a properly rooted RemixOS

For RemixOS UEFI/ESP installs (32 & 64 bit)

Part 1 You will also want to make sure you can view hidden and system files in Explorer options (if you need to , google it), Once you do that, hit the start menu, and type in CMD, and then right click, and open as administrator. It should look like the window image attached to this post.

Once that is open, type in:

mountvol X: /S

Then check to see if it is mounted already, (thanks to: [MENTION=4666322]Ventricle[/MENTION])

Start Task Manager; a) CTRL+ALT+DEL -> Task Manager b) CTRL+Shift+ESC c) Right click the taskbar and select Task manager.

Click "File" tab -> "Run new task" -> "Browse" -> "This computer" -> SYSTEM (X:) or type in "x:" in the filepath bar"

If you cannot access X:, then that could mean one of three things. 1) You have an ESP setup, and just need to scroll down to the ESP System Partition setups section, or 2) You have a legacy MBR setup and just don't know it. or 3) Your setup falls within the other category. Check below for some insight, or the second post for more links to help you figure things out.

ESP System Partition setups

Part 2 Now that we have the partition mounter, we can open Notepad++ or your favorite code editor as administrator (the same was as before, right click and open as administrator), and browse to X:\BOOT\grub\ and open grub.cfg (Explorer.exe will not show the mounted partition, so we use Notepad++ as an Admin to do this). Then add a second boot entry containing the REMOUNT_RW=1 entry like you see below: (mine might vary from yours a tiny bit)

menuentry 'Remix OS_x64' --class android {
search --file --no-floppy --set=root /RemixOS/kernel
linux /RemixOS/kernel root=/dev/ram0 androidboot.hardware=remix_x86_64 androidboot.selinux=permissive quiet SERIAL=random logo.showlogo=1 DATA= SRC=RemixOS CREATE_DATA_IMG=1
initrd /RemixOS/initrd.img
}

menuentry 'Remix OS_x64- RW' --class android {
search --file --no-floppy --set=root /RemixOS/kernel
linux /RemixOS/kernel root=/dev/ram0 androidboot.hardware=remix_x86_64 androidboot.selinux=permissive quiet SERIAL=random logo.showlogo=1 REMOUNT_RW=1 DATA= SRC=RemixOS CREATE_DATA_IMG=1
initrd /RemixOS/initrd.img
}

Save it and also do this for grub32.cfg & grub64.cfg if they are in that directory as well.

Now close Notepad++, then go back to the admin CMD prompt and type

mountvol X: /D

or if you used Z:

mountvol Z: /D

This will dismount the UEFI volume for safe reboot.

You can now reboot, and choose the entry you added. It will then extract the system.sfs file to a system_dev.img, and mount it as RW for you. Once booted, you can update SuperSU from Play store and enjoy a properly rooted RemixOS.

RemixOS OTA/Update Instructions:

So you got an OTA notification, or you downloaded the updated .zip from Jide's website. Now what? Well there are a few things we will have to do in preparation for the update. So I will provide a seperate set of instructions for each possible scenario.

While using RW enabled RemixOS

If you got a notification that the OTA was available while using the RW enabled entry, then we are going to have to make some sacrifices to let this go through successfully. First thing we are going to have to do is reboot back to Windows (or your standard OS), and find your RemixOS directory (usually C:/RemixOS/) and look for the system_dev.img file and delete it (yes, I am serious, just hit the delete button). This will of course cause a few of your ROOT apps and tweaks that were written to system to vanish, so after we are done, you will have to reapply/reinstall those.

Now we can reboot and make sure you choose the NON-RW boot entry for RemixOS. Once in RemixOS, go ahead and check for and apply the OTA update as normal. Once the update is complete, you can re-create the RW image by simply choosing the RW enabled boot entry.

Using the .zip from Jide's website

If you ended up grabbing the .zip file for the updated version of RemixOS, then we can upgrade manually with no issues usually, but you will have to do this from Windows (or your OS of choice).

Start by opening the .zip and extracting these files over the ones already in the RemixOS folder:

initrd.img

ramdisk.img

kernel

system.sfs

I also replace the install.img and isolinux.sys files, but I don't think they are needed. I'm just lazy and drag it all over from the .zip ;)

The next step is that same as the OTA update. You now have to delete your system_dev.img file. Once that is done, you can reboot and choose the RW enabled boot option to extract the system and enable RW.

Ubuntu based Instructions:

And for users who are running this on Ubuntu based systems, please follow [MENTION=6732000]Cyborg Ninja[/MENTION]'s instructions below:

Using EasyBCD or other methods

If you have installed RemixOS using EasyBCD with the .iso or similar method, you will need to remove your install, and then reinstall with a modified ISO.

Extract the .iso file to a folder on your computer, and inside that folder, you will see a few folders and then the .img files and such. To start, navigate to efi/RemixOS/ and add the second RW entry to the grub.cfg, grub32.cfg & grub64.cfg like the UEFI instructions from above, but no need to mount the UEFI partition here.

Once those are done, navigate back to the root of the extracted ISO, and then go to boot/grub/ and add your second entry to the grub.cfg in there too, use the Resident Mode entry from that though as your base, just adding the REMOUNT_RW=1 line to a copy of it. Save, exit, and go back to the root of the extracted ISO again.

Now enter the isolinux directory, and edit the isolinux.cfg file, adding the REMOUNT_RW=1 line to a copy of the "residentmode" entry. Save, exit,back to root of the extracted ISO again.

Now select all the files and folders, and using 7zip or comparable application, zip them all back into an .iso file. Then you just have to install this like you would normally using EasyBCD. Just a reminder though. This method is not recommended. I recommend using Jides installer or the roll your own UEFI method. Also, since I have no way of testing this method, I cannot verify it will work 100%. Awaiting user feedback on this :)

I hope this helps some of you get what you need with root. I personally create a separate root entry in my grub.cfg that let's me select standard or R/W, so in the event of an OTA update, it should be able to complete without issues.

Again, Thanks goes out to Jide, [MENTION=4666322]Ventricle[/MENTION], [MENTION=4762414]lollyjay[/MENTION], & [MENTION=6732000]Cyborg Ninja[/MENTION] for all the help so far on this :)