Welcome to the forum,
Basically you need to change fstab (and optionally the SD card) as follows:
a) Use blkid to identify the SD boot partition UUID (/dev/mmcblk0p1 in my case)
b) Use sudo nano /etc/fstab and change the /boot line to have this UUID rather than the HDD UUID
c) Use sudo fdisk to delete the Linux partition off the SD card (I used sudo disk /dev/mmcblk0 and pd2dw) - THIS IS OPTIONAL
e) apt update and upgrade
f) Configure Pi as required
Have a look at https://www.raspberrypi.org/forums/view ... 1&t=244965
for a walk through.
Need Pi spray - these things are breeding in my house...