One of the most severe limits on Raspian/Raspberry Pi OS was having to boot the Raspberry pi computer from a (relatively slow) Micro SD card. One of the “work-arounds” has been to use something like “Bootberry 2.0” on the SD Card and through it, install multiple operating systems on a Solid State Drive (SSD) connected via USB.
On June 15th, 2020, Raspberry Pi OS moved a new bootloader that had been in Beta out to Stable, then made a new Stable Release available to apt the next day. Using the same RPi4 8gb I have been working with recently, this morning I opened a terminal and ran:
sudo apt update && sudo apt full-upgrade
reboot
When the system came back, opened another terminal session and ran:
sudo nano /etc/default/rpi-eeprom-update
Edited the file to use stable as the default version. (Ctrl-X, y, Enter to save & get out of nano) Then I ran the above command again just to be certain it now was on stable.
In the same terminal session, then ran:
sudo rpi-eeprom-update -d -f /lib/firmware/raspberrypi/bootloader/stable/pieeprom-2020-06-15.bin
reboot
After rebooting used SD Card Copier utility from “Main manu | Accessories” to copy system from SD Card to my SSD. You will want to be careful you are selecting the correct device names in the “from” and “to” drop-down windows.
When that process was completed, I did a shutdown and power down, removed the old Micro SD card, powered back up and after a few seconds my little system booted up off of the SSD. Nice!