Creating floppy disk images from folders of data files for VirtualBox

VirtualBox is able to pass floppy disk images (in a format called IMA) to VMs. For a data preservation project, I need to create a lot of those images. My host system is macOS 11.6 Big Sur, and I have Homebrew tools available. My data files are on my APFS disk, in a folder hierarchy where every folder contains the files that were originally on the corresponding floppy. Those folders seem to have been created by just copying floppy contents on an old DOS/Win311 machine. Example: disk1 file1.ext file2.ext disk2 another1.txt another2.txt None of the disks need to be bootable, so boot sector creation is irrelevant in this context. I tried to just create the images using hdiutil, but the resulting image files would not work: hdiutil create -size 1440k -fs "MS-DOS FAT12" -layout NONE -srcfolder disk2 -format UDRW -ov diskimage2.ima So, can you suggest a (scriptable, non-interactive) way to go through a folder hierarchy and convert every folder to a disk image for VirtualBox containing that folder's files?