just tried to install 6.7 & then 7.2 (via Ventoy) to an USB stick, could not resize USB fat32 partition
does sparky not include msdos vfat fat32 support when booting from Ventoy?
or missing from ISO build?
I use Etcher and have never had a problem with a fat32 formatted USB drive to write Sparky or any Linux OS to it.
Are you using Linux or Windows to write the OS to the USB drive?
Also why are you trying to resize the partition? That should get done automatically.
followup
seem to be running into a problem
after install of 7.5
it does not look for windows OS when making grub,
insmod vfat
is missing in grub.cfg?
Check if os-prober is disabled be default. That has been done as a security measure.
Add/edit the following line to your /etc/default/grub file, then run update-grub.
Change:
GRUB_DISABLE_OS_PROBER=true
to:
GRUB_DISABLE_OS_PROBER=false
then update grub.