Good evening and thanks to Raspberry dev team for this.
It 's working with me, I already used SSD for root but not for bootloading. Now I don't have anymore SD card in reader. Looking for a dumb plastic card for protecting the SC card reader from dust now
There is the good.
There is also an issue (there is always one?)
When "sudo reboot", the Raspberry pi never boot and is hanged on screening errors on sdcard and MSD usb. I have a TV connected, but not all the time
I have a button to cut the power, and just after it works.
I have no idea why,
* running my SSD on UGREEN 3.0 and 3.1 adapter, same issue.
* I had also a USB 3.1 sabrent adapter, but same issue (understood this one was not a good one)
Didn't tried on USB 2 USB port, I'm not buying SSD for using it on USB 2.0 adapter
I don' have any serial cable (and honestly threw them in the trash since my graduation 20 years before), maybe because may last computer with COM serial port was Pentium MMX
I can also afford one if needed, but for me it's a little regression (remembering my 56Kbps modem, gosh that's a long time...) and don't really know hom I will connect on my laptop with not even a PS/2 connectic
I would say that "reboot" command is really needfull, and needing to manually switch of the pi is not an option for me (lazy guy, plus need to reboot from outside the house)