I have been able to install /e/OS 2.7-u on my SM-T500 using Heimdall on Ubuntu Linux, without Odin.
After the prerequisites (Bootloader, OEM, adb), I installed /e/OS recovery with Heimdall (I renamed recovery file in recovery.img) and the Galaxy Tab in download mode.
sudo heimdall flash --RECOVERY recovery.img --no-reboot
After that, it’s very important to reboot into recovery as said by the install page.
Then I followed steps to install /e/OS from recovery.
At this point, I couldn’t boot the Galaxy Tab because of a looping reboot.
So I downloaded vbmeta.img file from here and flashed it with Heimdall (Galaxy Tab in download mode) :
sudo heimdall flash --VBMETA vbmeta.img
And then it worked ! 
Perhaps I could have used the vbmeta.img file from the /e/OS build zip file but I didn’t try.
Thank you for this info. I was having the same issue and was able to finish the flashing because of your remark. 
Hi all, a quick feedback from me - instructions on /e/os website did not work for me with A14, as the tablet would bootloop with vbmeta / validation failure during second boot of factory reset (stock android) even though flashed correctly. I had to re-flash with stock os before trying again.
Then: Tried again now when A15 came out, flashing recovery directly after vbmeta (reboot into Download once more) worked for me fine. Some details below, for anyone who is stuck in a similar point still.
- Used Windows 11 in the VM (VirtualBox) under Arch Linux to flash Odin (remember to connect us device to vm in toolbar after boot into download!
) - followed instructions for preparation (downloads, vbmeta.tar and recovery.tar), unlock, quick setup android, USB debugging enabled, device authorized… then finally boot into Download
- flash vbmeta (Odin AP), disable auto-reboot and reboot manually
- Boot into download again, flash recovery as in instructions, reboot manually
- IMMEDIATELY after reboot, boot into recovery mode (volume up).
- Rest of the steps as in the instructions (format and install).
(- Installed /e/os with adb sideload from Linux shell now)
Translated with DeepL.com (free version)
Hey,
please edit the install instructions. It took me hours (and others) to find out what the hack is going on with this bootloop. Goudi came up with the shortest sollution:
So I downloaded vbmeta.img file from here and flashed it with Heimdall (Galaxy Tab in download mode) :
sudo heimdall flash --VBMETA vbmeta.img
it just means: Flash the vbmeta.img at the very end, and everything is fine!
Please please add this - it will save a lot of time for others.
Ray