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[Q] Help, Xoom locked on red M screen, device not recognized

Hi, partial noob here, I've rooted a different Xoom but this one was stock US wifi only, MZ604.
Amazon appstore was restarting continually so I navigated away but left it open. Later in the day when I tried to reopen it, it crashed my Xoom. Now it is locked on red M screen. I can soft resest and get to "starting fastboot protocol support" but when connected to pc with oem usb cable, it doesn't show up under adb devices. If I adb reboot bootloader, it says device not found. I have checked my drivers, they show up under "Mot Single ADB Interface" with file version 1.1.0.0 and file version 1.7.6001.0 (two drivers). I have adb and fastboot in my SDK_tools folder, what am I missing?
Thanks for any help,
Peter

pepond said:
Hi, partial noob here, I've rooted a different Xoom but this one was stock US wifi only, MZ604.
Amazon appstore was restarting continually so I navigated away but left it open. Later in the day when I tried to reopen it, it crashed my Xoom. Now it is locked on red M screen. I can soft resest and get to "starting fastboot protocol support" but when connected to pc with oem usb cable, it doesn't show up under adb devices. If I adb reboot bootloader, it says device not found. I have checked my drivers, they show up under "Mot Single ADB Interface" with file version 1.1.0.0 and file version 1.7.6001.0 (two drivers). I have adb and fastboot in my SDK_tools folder, what am I missing?
Thanks for any help,
Peter
Click to expand...
Click to collapse
Are you rooted with custom recovery or stock? After soft reset when the "M" first appears count to three and press the volume down button, hopefully you will see "android recovery". If you do press the volume up button to enter recovery and you could do a system restore from it. I'm thinking maybe you didn't have "usb debugging" turned on in developer settings, does it show a pop up on your computer when you plug in the xoom where you can browse it's file contents? If so save any photos or important docs and do a system restore like I explained earlier.

Same woes here
solved

[Q] [HELP]Moto G (4.4.2) USB debugging wont work

Hey guys, i have the following problem.
So I want to unlock the bootloader of my Moto G but to do that I must use USB debugging. But if I use the command "adb devices" it gets always shown as offline. So I did a little research and found out, that since 4.4.2 a Pop-Up should show up to allow USB debugging with the connected PC.
Problem is this Pop-Up won't show up...
Could you please help me. I couldn't find a solution. Really frustating

Have you enabled USB debugging in Developer Options in settings?
Sent from my XT1032 using Tapatalk

Of course I did ^^

battlemaxi said:
Hey guys, i have the following problem.
So I want to unlock the bootloader of my Moto G but to do that I must use USB debugging. But if I use the command "adb devices" it gets always shown as offline. So I did a little research and found out, that since 4.4.2 a Pop-Up should show up to allow USB debugging with the connected PC.
Problem is this Pop-Up won't show up...
Could you please help me. I couldn't find a solution. Really frustating
Click to expand...
Click to collapse
For my XT1031, I had to use the Motorola USB drivers for ADB to work, and Kush's Universal ADB drivers for Fastboot to work.
And if you are using Windows 8/8.1, then you have to disable to forced signature verification in order to install the Universal ADB drivers.
Also, for ADB to work in Windows, I had to set the phone's USB computer connection to Camera (PTP), instead of Media Device.

I'm using Motorolas Drivers. I downloaded them from the official website.
My ADB is also on the latest version (1.0.3.1). Also tried to factory reset my phone. Nothing works, the pop-up wont show up...

battlemaxi said:
I'm using Motorolas Drivers. I downloaded them from the official website.
My ADB is also on the latest version (1.0.3.1). Also tried to factory reset my phone. Nothing works, the pop-up wont show up...
Click to expand...
Click to collapse
Dude, you need to follow the instructions step by step and provide more info about what's going on.
1. Is your "Enable ADB debugging" enabled? You said yes.. does your phone show "Android debugging enabled" icon when you plug it into your computer? If not, you don't have it enabled !
2. If you see the notification, go to Device Manager (hope you are using Windows, or I can't really help you), then can you find your device there? If the USB drivers are installed correctly, then you should see "Android Device" then a "Motorola ADB Interface" inside it. If not, you will see a yellow exclamation with something like "Motorola device"..
3. Did you change your phone's USB computer connection to Camera (PTP)??

If adb says that the device is "offline" but you see its ID, then you didnt authorize (on the phone) the pc to access USB Debugging, its a new feature of 4.4.When you connect your phone, a prompt should appear (check the status bar if it doesnt), saying a computers with RSA Key XX:XX:XX:XX:XX:XX:XX requested access to USB Debugging.
good luck

First of thanks for your help, much appreciated
1. Yes I have USB debugging enabled. If I plug in my Moto G a icon appears in the Notification-Center which says "USB debugging activated"
2. Yes if I go into the Device Manager I can see Android Device
3. Yes I ded change my USB-Setting to PTP
Any other ideas ?

battlemaxi said:
First of thanks for your help, much appreciated
1. Yes I have USB debugging enabled. If I plug in my Moto G a icon appears in the Notification-Center which says "USB debugging activated"
2. Yes if I go into the Device Manager I can see Android Device
3. Yes I ded change my USB-Setting to PTP
Any other ideas ?
Click to expand...
Click to collapse
Actually you do not need adb to unlock the bootloader only mfastboot which does not need adb to work all you do is boot into the bootloader then follow this
http://forum.xda-developers.com/showpost.php?p=47705438&postcount=6

liveroy said:
If adb says that the device is "offline" but you see its ID, then you didnt authorize (on the phone) the pc to access USB Debugging, its a new feature of 4.4.When you connect your phone, a prompt should appear (check the status bar if it doesnt), saying a computers with RSA Key XX:XX:XX:XX:XX:XX:XX requested access to USB Debugging.
good luck
Click to expand...
Click to collapse
As mentioned above (first post of the thread) I know that I gotta allow my PC to connect properly to the phone. But the problem is that pop-up thingy wont show up. So I'm not able to allow USB debugging for my PC...
robin0800 said:
Actually you do not need adb to unlock the bootloader only mfastboot which does not need adb to work all you do is boot into the bootloader then follow this
http://forum.xda-developers.com/showpost.php?p=47705438&postcount=6
Click to expand...
Click to collapse
Everytime I try to do this i get the errormessage, that those commands or not known even if I'm at the right folder with the fastboot.exe within it. Because of that I thought I would need the connection to be online (I'm kinda new to all of this ).

battlemaxi said:
As mentioned above (first post of the thread) I know that I gotta allow my PC to connect properly to the phone. But the problem is that pop-up thingy wont show up. So I'm not able to allow USB debugging for my PC...
Everytime I try to do this i get the errormessage, that those commands or not known even if I'm at the right folder with the fastboot.exe within it. Because of that I thought I would need the connection to be online (I'm kinda new to all of this ).
Click to expand...
Click to collapse
Just follow those instructions to the letter and any thing you don't understand or get an error message report back here

battlemaxi said:
First of thanks for your help, much appreciated
1. Yes I have USB debugging enabled. If I plug in my Moto G a icon appears in the Notification-Center which says "USB debugging activated"
2. Yes if I go into the Device Manager I can see Android Device
3. Yes I ded change my USB-Setting to PTP
Any other ideas ?
Click to expand...
Click to collapse
Hmmm... so.. what do you see when you type "adb devices" ?
Also, in your Device Manager, is the Motorola ADB interface properly installed? (no issues)?
And yes, to unlock the bootloader you just need Fastboot... when you boot to Fastboot and type "fastboot devices" do you see anything?

Okay, I will Unlock my Bootloader tomorrow but I would like to fix this issue, because I might encounter it in the future :/

battlemaxi said:
Okay, I will Unlock my Bootloader tomorrow but I would like to fix this issue, because I might encounter it in the future :/
Click to expand...
Click to collapse
Well, are you sure you fastboot works?
If so, it's very weird why adb won't...
And yeah, ADB is very useful... if not lifesaving...

Okay I'm sure fastboot works, cause I just unlocked my phone. So got anyone any ideas how I could Allow USB debugging ? :/

battlemaxi said:
Okay I'm sure fastboot works, cause I just unlocked my phone. So got anyone any ideas how I could Allow USB debugging ? :/
Click to expand...
Click to collapse
Can you see adb in the computer device manager program

battlemaxi said:
Okay I'm sure fastboot works, cause I just unlocked my phone. So got anyone any ideas how I could Allow USB debugging ? :/
Click to expand...
Click to collapse
Couldn't wait till tomorrow to unlock the bootloader huh?
Hmm... Did you use the Motorola USB drivers from the Motorola Device Manager 2.4.5?
And everything is properly installed in Device Manager? No devices with yellow exclamation?
And ADB devices shows no list of devices attached?
So weird...

battlemaxi said:
As mentioned above (first post of the thread) I know that I gotta allow my PC to connect properly to the phone. But the problem is that pop-up thingy wont show up. So I'm not able to allow USB debugging for my PC...
Everytime I try to do this i get the errormessage, that those commands or not known even if I'm at the right folder with the fastboot.exe within it. Because of that I thought I would need the connection to be online (I'm kinda new to all of this ).
Click to expand...
Click to collapse
You can revoke all authorized devices for adb access.The option is right below the USB Debugging switch in Developer Options.
Then reboot your moto g and try again.

liveroy said:
You can revoke all authorized devices for adb access.The option is right below the USB Debugging switch in Developer Options.
Then reboot your moto g and try again.
Click to expand...
Click to collapse
Even if you revoke, you should see the device listed if you run "adb devices"...

neozen21 said:
Couldn't wait till tomorrow to unlock the bootloader huh?
Hmm... Did you use the Motorola USB drivers from the Motorola Device Manager 2.4.5?
And everything is properly installed in Device Manager? No devices with yellow exclamation?
And ADB devices shows no list of devices attached?
So weird...
Click to expand...
Click to collapse
Nope
I guess I have the newest Version, cause I downloaded it from Motorola.com
Yes everything is working no yellow thingys what so eher..
If I use the 'ADB devices' command the ID of my device shows up but as already mentioned it's offline.
Gesendet von meinem XT1032 mit Tapatalk

[GUIDE] [T-MOBILE] Unlock bootloader

Warning: This will delete all your data. You'll also see a large warning every time you turn on the device (attached), this disappears in less than a second.
Turn on developer mode
Turn on OEM unlock and USB debugging
Install LG drivers
Windows: http://tool.lime.gdms.lge.com/dn/downloader.dev?fileKey=UW00120120425
Mac: http://tool.lime.gdms.lge.com/dn/downloader.dev?fileKey=UW00320110909
Type adb devices and authorize your computer on the phone
Type adb reboot bootloader
Type fastboot devices and make sure your phone shows up
Type fastboot oem unlock
Type fastboot getvar all
Should say (bootloader) unlocked:yes
Type fastboot reboot

What's the purpose for an Unlock bootloader?

bhagiratha said:
What's the purpose for an Unlock bootloader?
Click to expand...
Click to collapse
It's the first step to rooting. If you plan to root, wiping your data now may be preferable.

bhagiratha said:
What's the purpose for an Unlock bootloader?
Click to expand...
Click to collapse
At this point, nothing. It's a prelude to rooting.

When I type in fastboot oem unlock, I get < waiting for any device >
And it waits, forever. (well, ok, like 15 minutes until I get impatient and pull the battery)
I'm on windows 10, installed the drivers from this post. When I check the device manage, the phone is listed as Android Bootloader Interface. I try updating the drivers by pointing it to the LG drivers folder, it says drivers are up to date. I've got ADB and OEM unlock both enabled in developer options. I've tried the phone on different USB ports, the cable works fine when the phone is booted normally, I've tried launching minimal adb&fastboot as admin and regular. What am I missing/doing wrong?

heldc said:
When I type in fastboot oem unlock, I get < waiting for any device >
And it waits, forever. (well, ok, like 15 minutes until I get impatient and pull the battery)
I'm on windows 10, installed the drivers from this post. When I check the device manage, the phone is listed as Android Bootloader Interface. I try updating the drivers by pointing it to the LG drivers folder, it says drivers are up to date. I've got ADB and OEM unlock both enabled in developer options. I've tried the phone on different USB ports, the cable works fine when the phone is booted normally, I've tried launching minimal adb&fastboot as admin and regular. What am I missing/doing wrong?
Click to expand...
Click to collapse
Try fastboot devices and reinserting the usb cable. Doesn't make sense that adb sees it but fastboot does not unless it's a different driver. I think fastboot driver differs actually so do that driver too.

Ubuntu
heldc said:
When I type in fastboot oem unlock, I get < waiting for any device >
And it waits, forever. (well, ok, like 15 minutes until I get impatient and pull the battery)
I'm on windows 10, installed the drivers from this post. When I check the device manage, the phone is listed as Android Bootloader Interface. I try updating the drivers by pointing it to the LG drivers folder, it says drivers are up to date. I've got ADB and OEM unlock both enabled in developer options. I've tried the phone on different USB ports, the cable works fine when the phone is booted normally, I've tried launching minimal adb&fastboot as admin and regular. What am I missing/doing wrong?
Click to expand...
Click to collapse
You can also load Ubuntu on a flash drive and boot your computer from the flash drive. Then run the commands.
https://www.ubuntu.com/
Cheers

heldc said:
When I type in fastboot oem unlock, I get < waiting for any device >
And it waits, forever. (well, ok, like 15 minutes until I get impatient and pull the battery)
I'm on windows 10, installed the drivers from this post. When I check the device manage, the phone is listed as Android Bootloader Interface. I try updating the drivers by pointing it to the LG drivers folder, it says drivers are up to date. I've got ADB and OEM unlock both enabled in developer options. I've tried the phone on different USB ports, the cable works fine when the phone is booted normally, I've tried launching minimal adb&fastboot as admin and regular. What am I missing/doing wrong?
Click to expand...
Click to collapse
First be on your c:\
Type in adb devices
If your phones serial comes up type in..
Adb reboot bootloader
Then
Fastboot oem unlock

ADB reboot bootloader boots straight into the OS on AT&T v20 :crying:

cordell12 said:
ADB reboot bootloader boots straight into the OS on AT&T v20 :crying:
Click to expand...
Click to collapse
Do you guys have the oem unlock option at least?

Also what helped me was downloading android studio with the sdk.. It installs android drivers which were necessary for me at least to get past the waiting for device message, windows located the drivers on my c drive and boom... Unlocked Bootloader.. Just saying
Sent from my LG-H918 using XDA-Developers mobile app

wing_addict_usa said:
Do you guys have the oem unlock option at least?
Click to expand...
Click to collapse
yup, even warns us that certain things won't work if we enable it. adb works just fine too

cordell12 said:
yup, even warns us that certain things won't work if we enable it. adb works just fine too
Click to expand...
Click to collapse
Yeah I am really curious if there may still be a way to unlock the bootloader with out AT&T variant. I wish I kept my phone on the Download Mode when I had gotten into it because I wanted to see if by any chance that might actually get fastboot to read the phone..
I'm curious if there's anyone with a T-Mobile variant that has their bootloader unlocked and wants to view their debug logs (specifically last_log/last_kmsg). As I was looking through mine and tried to boot into bootloader these lines were the only things I saw that might have interested me at all. I'm just curious on what the values are on their phone.
Code:
last_log
[ 0.711419] ro.boot.flash.locked=1
[ 0.711784] ro.bootloader=unknown
[ 0.711817] ro.oem_unlock_supported=1
last_kmsg
<6>[ 1.077087 / 01-01 00:00:01.069][3] [70] SW3800_Authentication [vendor code: 1]
<6>[ 1.077120 / 01-01 00:00:01.069][3] [110] set_dload_mode: download_mode:0

wing_addict_usa said:
It's the first step to rooting. If you plan to root, wiping your data now may be preferable.
Click to expand...
Click to collapse
It's quite possible the process of rooting will wipe the phone anyway.

twistedvip said:
Yeah I am really curious if there may still be a way to unlock the bootloader with out AT&T variant. I wish I kept my phone on the Download Mode when I had gotten into it because I wanted to see if by any chance that might actually get fastboot to read the phone..
I'm curious if there's anyone with a T-Mobile variant that has their bootloader unlocked and wants to view their debug logs (specifically last_log/last_kmsg). As I was looking through mine and tried to boot into bootloader these lines were the only things I saw that might have interested me at all. I'm just curious on what the values are on their phone.
Click to expand...
Click to collapse
power device off, hold volume up and keep it down and plug in USB cord while it's connected to PC. I tried fastboot from download mode though. the logs do look interesting, wonder what a T-MOBILE device says

Double0EK said:
First be on your c:\
Type in adb devices
If your phones serial comes up type in..
Adb reboot bootloader
Then
Fastboot oem unlock
Click to expand...
Click to collapse
Yup, I did that. And then I get an error. Well, not an error, just a lack of response. fastboot devices returns nothing. I'm currently downloading the full sdk, on the theory that perhaps it's a problem with the installation of 'minimal adb and fastboot' I have.
---------- Post added at 08:07 PM ---------- Previous post was at 07:36 PM ----------
manufan721 said:
Also what helped me was downloading android studio with the sdk.. It installs android drivers which were necessary for me at least to get past the waiting for device message, windows located the drivers on my c drive and boom... Unlocked Bootloader.. Just saying
Sent from my LG-H918 using XDA-Developers mobile app
Click to expand...
Click to collapse
Did you do anything specific after installing Android Studio to get it to install the drivers? Cos I've installed Android Studio, but am still having the same problem-fastboot devices returns nothing, and fastboot oem unlock hangs on <waiting for device>. I went into device manager and had it search the entire C: for drivers for the android bootloader interface, and it gave the same 'already up to date drivers' message as before I installed Android Studio.
EDIT- Even after installing the Google usb driver, no luck. Giving up for the weekend.

I'm a newbie, may I know have to fastboot from download mode?

having same issue just hangs at Fastboot oem unlock if anybody can help thanks in advance

twistedvip said:
Yeah I am really curious if there may still be a way to unlock the bootloader with out AT&T variant. I wish I kept my phone on the Download Mode when I had gotten into it because I wanted to see if by any chance that might actually get fastboot to read the phone..
I'm curious if there's anyone with a T-Mobile variant that has their bootloader unlocked and wants to view their debug logs (specifically last_log/last_kmsg). As I was looking through mine and tried to boot into bootloader these lines were the only things I saw that might have interested me at all. I'm just curious on what the values are on their phone.
Code:
last_log
[ 0.711419] ro.boot.flash.locked=1
[ 0.711784] ro.bootloader=unknown
[ 0.711817] ro.oem_unlock_supported=1
last_kmsg
<6>[ 1.077087 / 01-01 00:00:01.069][3] [70] SW3800_Authentication [vendor code: 1]
<6>[ 1.077120 / 01-01 00:00:01.069][3] [110] set_dload_mode: download_mode:0
Click to expand...
Click to collapse
[ 0.711817] ro.oem_unlock_supported=1 1=YES
did some digging into last_kmsg while trying to boot into bootloader (AT&T device) and found a reason it may not be allowing it.
http://forum.xda-developers.com/showthread.php?t=2708466
Its a start :good:
of course we need root in order to dd anything

LG issued a new driver update for the v20. Driver version is 4.1.1+. You can get the driver from the website.

Shield K1 Tablet isn't recognized by fastboot

Good afternoon everyone
I got my K1 for Christmas and I've been trying to root it for a few days but I can't get that far because I can't get the bootloader unlocked.
I've been following the guide based off of Nvidia's website
I've activated USB Debugging mode as seen here . Now once I've authorized the PC using the tablet. Once I run cmd in administrator mode I run
Code:
adb devices
I am able to get the serial and it says it's authorized. However if I go into Fastboot. if I check for devices it just goes back to the prompt, and if I try to run the unlock command it just gets stuck on <waiting for devices> (I've attached a screenshot here.)
At first I thought this was an issue with the OS/Drivers because I am on Win10 x64, and the shield drivers gave some error about driver incompatibility. So I loaded up a VM with win7 x32. However I am running into the exact same issue once I get to fastboot; the tablet just doesn't want to cooperate. I've booted into fastboot manually Where the options are:
Code:
[nvtboot] (version UNDEF_BUILD)
[bootloader] (version UNDEF_BUILD)
Device - locked
Continue
Fastboot Protocol
Recovery Mode
Restart
Poweroff
Nothing is recognized from there either. I've also tried multiple cables, since the Shield doesn't come with any. Anyways I've searched the older threads here for help but none of them have given me any luck. If there's something I can try I would definitely be open to hearing it and trying, I just don't know what the issue could be.
Thanks for your time everyone.

You have boot into the bootloader before being able to use fastboot. Just reboot your device and hold vol- during startup. The tablet will show some console messages, offering some options. If you see that screen, you can use fastboot.

bob3rt said:
Good afternoon everyone
I got my K1 for Christmas and I've been trying to root it for a few days but I can't get that far because I can't get the bootloader unlocked.
I've been following the guide based off of Nvidia's website
I've activated USB Debugging mode as seen here . Now once I've authorized the PC using the tablet. Once I run cmd in administrator mode I run
Code:
adb devices
I am able to get the serial and it says it's authorized. However if I go into Fastboot. if I check for devices it just goes back to the prompt, and if I try to run the unlock command it just gets stuck on <waiting for devices> (I've attached a screenshot here.)
At first I thought this was an issue with the OS/Drivers because I am on Win10 x64, and the shield drivers gave some error about driver incompatibility. So I loaded up a VM with win7 x32. However I am running into the exact same issue once I get to fastboot; the tablet just doesn't want to cooperate. I've booted into fastboot manually Where the options are:
Code:
[nvtboot] (version UNDEF_BUILD)
[bootloader] (version UNDEF_BUILD)
Device - locked
Continue
Fastboot Protocol
Recovery Mode
Restart
Poweroff
Nothing is recognized from there either. I've also tried multiple cables, since the Shield doesn't come with any. Anyways I've searched the older threads here for help but none of them have given me any luck. If there's something I can try I would definitely be open to hearing it and trying, I just don't know what the issue could be.
Thanks for your time everyone.
Click to expand...
Click to collapse
Adb works in normal mode.
Fastboot works in Bootloader mode.
Reboot to BL and type "fastboot devices", if no device go to K1 and select "fastboot protocol". Select on/yes.

dzidexx said:
Adb works in normal mode.
Fastboot works in Bootloader mode.
Reboot to BL and type "fastboot devices", if no device go to K1 and select "fastboot protocol". Select on/yes.
Click to expand...
Click to collapse
Hey there, sorry for my late reply, I've been swamped with work. I've tried your advice with no luck so far.
I can reboot to the bootloader, but when I select "fastboot protocol" I don't get to choose Select on/yes. it just refreshes the screen with the same options that I listed above. If you'd like when I get home I can provide a screenshot of my tablet so you can see the options, but I'm not getting anything like you described. Am I missing something?
Thank you for your time so far helping me.

Connect k1 to pc, type in cmd:
adb devices
adb reboot bootloader
fastboot devices
/Enable fastboot protocol on k1, type again/
fastboot devices
Give here screenshot from pc - all command/answers in cmd. @bob3rt

I had the same issue and lasted untill I tried different usb cable
Shield K1 connectivity is very sensible to cable quality
try others

dzidexx said:
Connect k1 to pc, type in cmd:
adb devices
adb reboot bootloader
fastboot devices
/Enable fastboot protocol on k1, type again/
fastboot devices
Give here screenshot from pc - all command/answers in cmd. @bob3rt
Click to expand...
Click to collapse
Hey Sorry again for a late response! However the good news is that I got it working!
What I ended up doing was hooking up the tablet to my Raspberry Pi with MATE and running adb/fastboot there. I originally ran into the same issue, but since I was able to sudo fastboot everything was recognized and seemed to work fine. I appreciate all of your help, and I apologize once again for the late replies!

For those that don't have a Raspberry Pi to follow the OP solution (like me), it's likely that your drivers aren't up to date on your PC.
Go here... https://docs.nvidia.com/gameworks/content/devices/shield_flashing_from_image.htm
And follow the initial instructions in the introduction paragraph and get yourself NVIDIA CodeWorks for Android. Once downloaded and installed you'll then see the shield in your fastboot devices list.
:good:

0mad said:
For those that don't have a Raspberry Pi to follow the OP solution (like me), it's likely that your drivers aren't up to date on your PC.
Go here... https://docs.nvidia.com/gameworks/content/devices/shield_flashing_from_image.htm
And follow the initial instructions in the introduction paragraph and get yourself NVIDIA CodeWorks for Android. Once downloaded and installed you'll then see the shield in your fastboot devices list.
:good:
Click to expand...
Click to collapse
Worked like a charm! Thanks.

Fastboot unlock doesn't work on brand new 4a.

Hi guys,
Bit stuck, couldnt find a google thingy to help me out.
Setup:
W10 (also tried on Arch)
Latest version of platform tools
Tried multiple cables
No hub between computer and phone, straight to back of the motherboard
OEM Unlock > Enabled
USB Debugging > Authorised and remembered
adb devices gives a valid output
adb reboot bootloader > reloads to Fastboot Mode (the one with the red exclamation mark)
> bootloader version s5-0.2-6539975
NOS Production: yes
Device state: locked
on computer:
fastboot flashing unlock
< waiting for any device >
No prompt on phone, at all.
Also not working in fastbootd menu.
I followed along with the guides I found online, but no luck. Am I forgetting something stupid?
Any help would be appreciated.
Thanks ever so kindly.

Hi, I have had similar in the past when not using the latest ADB version.
Just double check you are up to date

To add: fastboot devices does not give output, however the computer does chime when connected.

minty1978 said:
Hi, I have had similar in the past when not using the latest ADB version.
Just double check you are up to date
Click to expand...
Click to collapse
Yeah, I'm on version 30.0.5 (November 2020)

I just had to ask nicely.
sudo fastboot flashing unlock worked.
This can be closed:
Lesson: run fastboot as root or as admin.