Merge branch 'master' into pythonize

Let's catch up with the recent changes (boot-consistency merge, mainly).

Conflicts:
	Makefile
	raspi_master.yaml

raspi_master.yaml

@@ -134,14 +134,17 @@ steps:
       rm -rf /var/lib/apt/lists
 
   # Modify the kernel commandline we take from the firmware to boot from
-  # the partition labeled raspiroot instead of forcing it to mmcblk0p2
+  # the partition labeled raspiroot instead of forcing it to mmcblk0p2.
+  # Also insert the serial console right before the root= parameter.
   #
   # These changes will be overwritten after the hardware is probed
-  # after dpkg reconfigures raspi-firmware (upon first boot).
+  # after dpkg reconfigures raspi-firmware (upon first boot), so make
+  # sure we don't lose label-based booting.
   - chroot: /
     shell: |
-      sed -i 's/^/console=__SERIAL_CONSOLE__ /' /boot/firmware/cmdline.txt
-      sed -i 's/.dev.mmcblk0p2/LABEL=RASPIROOT/' /boot/firmware/cmdline.txt
+      sed -i 's/root=/console=__SERIAL_CONSOLE__ root=/' /boot/firmware/cmdline.txt
+      sed -i 's#root=/dev/mmcblk0p2#root=LABEL=RASPIROOT#' /boot/firmware/cmdline.txt
+      sed -i 's/^#ROOTPART=.*/ROOTPART=LABEL=RASPIROOT/' /etc/default/raspi-firmware
 
       __EXTRA_CHROOT_SHELL_CMDS__
 
@@ -160,6 +163,8 @@ steps:
   #   populated during installation.
   #
   # Note this will also trigger ConditionFirstBoot=yes for systemd.
+  # On Buster, /etc/machine-id should be an emtpy file, not an absent file
+  # On Bullseye, /etc/machine-id should not exist in an image
   - chroot: /
     shell: |
       rm -f /etc/machine-id /var/lib/dbus/machine-id