I am following this guide from Cyanogenmods to install TWRP on a Samsung Note 10.1 with Android 5.1.1 installed. I have activated USB Debugging in Developer options and connected the tablet to my computer, accepting the connection in the dialogue that pops up in the tablet. I then issue the adb command:
$ adb reboot bootloader
There is no error message, either on the computer or the tablet, and the tablet reboots.
I then issue the flash command:
$ fastboot flash twrp-3.0.2-0-lt03wifiue.img
< waiting for device >
And nothing else happens. The tablet remains silent and the command line in my computer is stuck. How do I move on from here?
Update I: This is the system and software in my computer:
$ uname -a
Linux ENG-PAVIL-PC2 4.4.0-87-generic #110-Ubuntu SMP Tue Jul 18 12:55:35 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
$ apt policy adb
adb:
Installed: (none)
Candidate: 1:6.0.1+r16-3
Version table:
1:6.0.1+r16-3 500
500 http://ch.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages
$ apt policy fastboot
fastboot:
Installed: (none)
Candidate: 1:6.0.1+r16-3
Version table:
1:6.0.1+r16-3 500
500 http://ch.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages
Update II: The bootloader version on this tablet is: P600XXUDQA1
Update III: heimdall was referenced below as an alternative to fastboot, but it is not able to communicate with the Samsung Note 10.1:
$ heimdall flash --no-reboot --RECOVERY twrp-3.0.2-0-lt03wifiue.img
Heimdall v1.4.1
Copyright (c) 2010-2014 Benjamin Dobell, Glass Echidna
http://www.glassechidna.com.au/
This software is provided free of charge. Copying and redistribution is
encouraged.
If you appreciate this software and you would like to support future
development please consider donating:
http://www.glassechidna.com.au/donate/
Initialising connection...
Detecting device...
ERROR: Failed to detect compatible download-mode device.
$ adb devices
List of devices attached
4300ee259691c037
device
Update IV: Still trying it out with heimdall, which so far is the only tool providing any bit of hope. For some reason it sometimes fails to identify Download mode - that is the reason for the error messages in Update III. By plugging in/out the USB cable and using the detect option one can eventually make sure it acquired the device:
$ heimdall detect
Device detected
Then the flash command succeeds:
$ heimdall flash --no-reboot --RECOVERY twrp-3.0.2-0-lt03wifiue.img
Heimdall v1.4.1
Copyright (c) 2010-2014 Benjamin Dobell, Glass Echidna
http://www.glassechidna.com.au/
This software is provided free of charge. Copying and redistribution is
encouraged.
If you appreciate this software and you would like to support future
development please consider donating:
http://www.glassechidna.com.au/donate/
Initialising connection...
Detecting device...
Claiming interface...
Setting up interface...
Initialising protocol...
Protocol initialisation successful.
Beginning session...
Some devices may take up to 2 minutes to respond.
Please be patient!
Session begun.
Downloading device's PIT file...
PIT file download successful.
Uploading RECOVERY
100%
RECOVERY upload successful
Ending session...
Releasing device interface...
Now things get tricky. If the tablet is rebooted normally after TWRP is flashed, the stock bootloader (I believe) will replace it automatically. In this case when the tablet is rebooted into recovery mode it will just run the stock Android recovery programme. It took me a while to figure this one out...
After flashing TWRP, the tablet must be rebooted directly into recovery mode. The problem is, it shows an error in the booting screen:
Could not do normal boot. Invalid KERNEL LENGTH!
TWRP does not load and the tablet just shuts down. That is how far I am right now.