KM You don't need supersu or root. You could install it later at any time, but it's not really needed. I think it has been superseeded by Magisk in the meantime.

SuperSU has been sold to a shady company and the source code was closed off. If you need root, use Magisk.

  • KM likes this.

    KM Basically you unlock the bootloader somewhere in the Android Settings. It's a simple switch. Then you get the latest TWRP image from twrp.me for the OnePlus 3. You reboot into fastboot mode

    Hey, sorry, I started working on this, but I find it a bit difficult as I do not have any background on the topic. I wonder whether you could clarify some doubts I have, before I make a mess...

    I am already stuck here. Pretty bad, uh?

    "Fastboot Install Method (No Root Required):
    You will need the platform-tools from the Android SDK on your computer. Find the Android command line tools section on the page linked and install the SDK tools package. From the SDK Manager, download only the platform-tools to get adb and fastboot binaries.    "

    So I need to install the SDK tools package, do not I? I am confused.

    • A few lines below on the same page I read "On your device, go into Settings -> About and find the Build Number and tap on it 7 times to enable developer settings. Press back and go into Developer Options and enable USB debugging."
      This seems to be something to be done within the OEM software? Is it necessary? It is not described in the XDA webpage.

    • Further down, "Your device needs to be unlocked before it can flash custom images. To unlock your device type: fastboot oem unlock".
      I guess it is something to be done via terminal, is not it? Is this what you meant in your old post with "Basically you unlock the bootloader somewhere in the Android Settings."?

    • Also, at https://www.androidtipsandhacks.com/root/twrp-the-complete-guide-to-using-recovery-on-android/, I read
      "To create a Nandroid backup tap the Backup option and choose the partitions to include. In most cases you should choose System, Data and Boot."
      I assume making an Android backup is something I shall do via TWRP before flashing the custom ROM? Would that allow me to restore the OEM software in case something goes wrong or PA does not work for me and I want to return/re-sell the phone?

    Sorry, I know it is a lot of questions...thank you very much in advance!

    • KM replied to this.

        I have never used Mac OS, can't help to get/install Android Tools. Maybe someone else can.

        You must enable developer options on the device by touching said entry 7 times. Then "Developer Options" appear as a new top-level item in Settings. Inside, there's "OEM unlocking" it must be enabled so you can later, with working Android Tools, enter the command "fastboot oem unlock". This would be denied otherwise. When everything worked, the bootloader is now unlocked.

        Once the bootloader is unlocked, you will see a message and a menu on every boot, as seen in this thread for example: https://forum.xda-developers.com/oneplus-3/help/help-how-to-remove-device-unlocked-t3425028
        They fixed the typo in a later firmware (those ship with new OxygenOS releases but can be installed separately with TWRP later if needed for some reason). Should you already see this menu on your device on every boot, it means the seller has already unlocked it and you could skip all those steps and "just" need to get Android Tools working on the Mac.

        • AGI replied to this.
        • AGI likes this.

          KM Many thanks!

          Did you create a Nandroid backup?

          Meanwhile after various attempts I think I found the right "command line tools only" at https://developer.android.com/studio/releases/platform-tools
          The downloaded folder finally contains fastboot. That should be sufficient, no need to install software on Mac as I was doing at the start.

          • KM replied to this.
          • KM likes this.

              AGI

              AGI I assume making an Android backup is something I shall do via TWRP before flashing the custom ROM? Would that allow me to restore the OEM software in case something goes wrong or PA does not work for me and I want to return/re-sell the phone?

              I should be possible with this method. However, there's also the unbrick tool which allows you to recover the device from a total soft brick (black screen at boot). It needs Windows. I did that several times and can confirm it works. Basically it writes back every partition to the device's memory using low-level hardware access: https://forums.oneplus.com/threads/guide-mega-unbrick-guide-for-a-hard-bricked-oneplus-3.452634/

              As long as TWRP still works, you could also install any OxygenOS version with TWRP, which will overwrite even TWRP.
              And as long as you have fastboot access, you should be able to install OxygenOS via command line, too.

              It might be useful to know which OxygenOS version you are on currently, just in case it is a very recent version that brought some firmware changes (might break TWRP or some custom ROMs' install routine).

              • AGI replied to this.

                    KM there's "OEM unlocking" it must be enabled so you can later, with working Android Tools, enter the command "fastboot oem unlock"

                    Thanks, this piece of information was missing on that webpage!

                    KM t might be useful to know which OxygenOS version you are on currently

                    The OxygenOS version is OP3_O2_open_25. Android version is 8.0.0 and Android security patch level is September 1, 2017.

                    I badly hope I won't need to reinstall it, but it is good to know there are options out there. Thanks!

                        Uhmmm, there is already a problem. I thought of checking I can use internet data within the original OS before installing PA. My SIM name is reported correct (with my Samsung Galaxy on5 from the US, no name would show up at all). However, I can't get online. I checked on the APNs ,and there are a bunch from Japan, but not mine. I am unable to create a new one specific to my carrier. From the little I read this option has disappeared after Marshmallow...
                        Furthermore, there are many posts from people who lost internet data after updating the software, e.g., https://forums.oneplus.com/threads/not-able-to-edit-add-apn-settings-in-op3.510771/, and they are not based in Asia...

                        Maybe PA will give me the chance to edit APNs?!?!

                        • KM replied to this.

                          AGI In the list of available APNs I see a "+" button, which allows to add an APN:

                          Not sure if this is what you'd need.

                            Yes, that is what I was looking for. Is that on PA? Thanks a lot! Then there is hope it does not work on Oxygen, but it will on PA.

                            I read drivers are not needed on Mac, but I am unable to see my phone upon launching ./fastboot devices.

                            When I reboot the phone and I choose fastboot mode, I do not have to anything else, do I? There is a green START in capital letters on top, then "FASTBOOT MODE" and "DEVICE STATE - locked" in red at the top and bottom, respectively, of a list of phone specs, like the product name and the serial number.
                            I just got the doubt I need to hit START...

                            • KM replied to this.

                              AGI Maybe you need to launch it as administrator/root, with elevated rights. I don't know anything about Mac OS, sadly.
                              Don't forget you'd need to put the device into fastboot mode first though, by holding down one of the volume buttons upon boot and then choosing fastboot. Not sure if it was up or down.

                              • AGI replied to this.

                                  KM Thanks. I am in fastboot mode. No need to hit START. That restarts the phone in normal mode.

                                  EDIT: I read that under Developer Options I should set Select USB Configuration to MTP (Media Transfer Protocol) rather than Charging, in order to be able to see the phone on the Mac. No improvement. However, every time I reboot from fastboot I see that the option has changed back to Charging...

                                  2nd EDIT: Same happens if I simply reboot without going thru fastboot. The USB configuration automatically reverts to Charging. If it happens to you too, then that is not the problem. I guess I will have to try with a Windows PC...

                                    I have been trying with a Windows 10 machine. The phone is not recognized. Among "Universal Serial Bus controllers" I find "Unknown USB Device (Device Descriptor Request Failed)". If I try to update the driver, Windows says the best driver is already installed. Under Properties I read "Windows has stopped this device because it has reported problems. (code 43). A request for the USB device descriptor failed". After a few seconds since the plugging-in, the unknown device disappears from the list. I tried to fix the code 43 error following this video, but the problem persists.

                                    • I am not sure whether the cable is the problem. Sadly, I do not have a spare.
                                    • In this video the guy confirms the USB configuration automatically reverts to Charging, which poses doubts on what the configuration is in fastboot.

                                    PS: Maybe I should have started a new thread on this install, I apologize. Happy to help out to move posts in case the moderators agree.

                                    • KM replied to this.

                                      The reason you have to install the developer tools is to get an ADB-friendly driver. I have no clue how to do this on the Mac, but on Windows you absolutely have to install the driver or ADB/Fastboot won't see the phone at all.

                                      • AGI replied to this.
                                      • KM likes this.

                                        The Windows drivers might be on the phone's memory and you could install them right from the connected phone that shows up as a drive.

                                        • AGI replied to this.

                                          Thanks to both. I installed the two drivers found at

                                          https://gsmusbdriver.com/oneplus-3

                                          but it did not work.
                                          I already tried with a virtual machine on Mac. It can't see anything, neither an external hard disk.
                                          I will see if I can find a Windows 7 machine.

                                          KM The Windows drivers might be on the phone's memory and you could install them right from the connected phone that shows up as a drive.

                                          Interesting point. However, it is not that my Mac or Windows machine can't see the phone in fastboot mode only, they can't see it all.

                                          Gurm The reason you have to install the developer tools is to get an ADB-friendly driver.

                                          Do you mean I shall install the 1GB Android Studio from https://developer.android.com/studio?

                                          • KM replied to this.

                                                AGI I still think using Linux could solve this issue the fastest.
                                                With Ubuntu: open a console, type
                                                sudo apt update
                                                sudo apt install android-tools-adb android-tools-fastboot
                                                Manjaro:
                                                sudo pacman -Sy android-tools

                                                    KM Uh, thanks, that sounds quite a stretch for my limited competences, and, also, I have only business devices around, so I need to watch out what I install...

                                                    I just tried on a Windows 7 laptop, and the phone is not recognized because malfunctioning. Even after installing the driver. Same as on the Windows 10 machine.

                                                    Other weird thing. I can't get online using internet data, as I said before. If I click on an existing APN setting, I am given the option to edit, I just realized, but the edits are not effectively taken into account. So, no improvement. However, to my surprise, I called myself from Skype and the phone rang. Maybe to an expert it is obvious why, but with my T-Mobile Samsung this sim card was not good at anything.

                                                      KM Versions of Android SDK tools from distributions are often disturbingly out of date.

                                                      (Mainly referring to Debian/Ubuntu, no idea about Manjaro)

                                                        Guess what?
                                                        I used a different USB-to-USB-C cable and the phone got recognized!

                                                        ./fastboot devices
                                                        c0dcc5f0 fastboot

                                                        However, I am encountering another issue which is not detailed in the tutorial

                                                        ./fastboot flash recovery twrp.img
                                                        Sending 'recovery' (27529 KB) OKAY [ 0.631s]
                                                        Writing 'recovery' FAILED (remote: 'Partition flashing is not allowed')
                                                        fastboot: error: Command failed

                                                        Any idea what is wrong this time?
                                                        Shall I unlocked the bootloader before flashing TWRP? I would think so, although I do not exactly know what I am doing and in the instructions I am following the unlocking is not mentioned in such order. On the phone screen I read DEVICE STATE - locked in red.

                                                        • KM replied to this.
                                                          dev