Yes you can upgrade NOOBS or PINN (enhanced version of NOOBS). NOOBS and PINN both uses two partitions on the Pi's boot system SD Card, /dev/mmcblk0p1 (a vfat boot partition) and /dev/mmcblk0p5 (a Linux display/selector/(/media/pi/SETTINGS) partition). To list files in NOOBS/PINN boot partition, it has to be mounted,
sudo mkdir /mnt/d1; sudo mount /dev/mmcblk0p1 /mnt/d1 then
ls -l /mnt/d1.
I would suggest to make a back up or your system first as if any thing goes wrong the only other recovery would be a fresh install.
Get the lastest copy of NOOBS
wget -O NOOBS_lite.zip https://downloads.raspberrypi.org/NOOBS_lite_latest or PINN
wget -O PINN.zip https://sourceforge.net/projects/pinn/files/latest/download
mkdir NOOBS or
mkdir PINN. Change to subdirectory
cd NOOBS or
cd PINN and unzip
unzip ../NOOBS_lite.zip or
runinstaller in the file
recovery.cmdline is for the new install. We are updating, not installing a new systems. THIS OPTION HAS TO BE REMOVED,
vi recovery.cmdline (Enter) cmd
dw to delete word
:wq (Enter) to save and exit (
:q! (Enter) to quit without saving if things goes wrong) (See WARNING at https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=142574&start=200#p1239359).
Remove the old NOOBS/PINN files from /dev/mmcblk0p1 that is mounted on /mnt/d1 previous,
sudo rm -R /mnt/d1/* and copy the new files
sudo cp -R * /mnt/d1/. Cleanup and sync,
sudo sync; sudo umount /mnt/d1; sudo rmdir /mnt/d1,
rm -R NOOBS* or
rm -R PINN*.
sudo reboot and and first boot on the new NOOBS or PINN and then to previous OS boot.