V20 Update error (Amazon Lightsail)

[rmalchi]

Hi all,
Just tried a couple of times to run the update from V18 update 9 (build 31) and getting the same error again:

(Reading database ... 95%
(Reading database ... 100%
(Reading database ... 52671 files and directories currently installed.)
Removing dphys-swapfile (20100506-5) ...
Setting up grub-pc (2.06-3~deb10u4) ...
/dev/sda does not exist, so cannot grub-install to it!
You must correct your GRUB install devices before proceeding:

DEBIAN_FRONTEND=dialog dpkg --configure grub-pc
dpkg --configure -a
dpkg: error processing package grub-pc (--configure):
installed grub-pc package post-installation script subprocess returned error exit status 1
Processing triggers for man-db (2.8.5-2) ...
Errors were encountered while processing:
grub-pc
E: Sub-process /usr/bin/dpkg returned an error code (1)
[33m====== [13:40:56] Upgrade Result: *******************************************[39m
{
"result": "Upgrade",
"time": "01-12-2024 13:40:56",
"title": "Package Update Failed",
"message": "An error occurred while upgrading package: remove dphys-swapfile"
}


Any ideas how to fix this error?

Thanks you all
Roi