Some USB sticks take some minutes of rest to become bootable
Some USB sticks are not detected as bootable just after installation. They need some minutes of rest before working.
I've seen this so many times that I don't doubt it anymore.
It happened again to several participants during the training in Brazil. (#19103 (closed))
The exact same procedure (waiting until balenaEtcher is done verifying) works fine with other USB sticks.
I'm seeing this a lot with Toshiba sticks (0930:6544
).
There's nothing we can do but let's see if we can add a note to the installation doc.