thanks for your hint.
Yes, I did it,
I had to choose the correct version of the boot eeprom to install.
sudo nano /etc/default/rpi-eeprom-update
Jumping from “default”, “stable”, "critical and “beta”
Flashing with :
sudo rpi-eeprom-update -d -a
And I finally succeeded in flashing the boot EEPROM by playing with “critical” or “beta” in place of “stable”, and forcing a specific version.
Here again, it works, but finally, I don’t know why as I made so many attempts, maybe is the latest action that solved the “boot order” problem, or flashing to another version before reflashing to the current.
But thanks for your analyze