FOSS gamedev and creative worlds

Hi there.
Recently my world became corrupted - migrating back&forth reset mapgen value so I had "flat" chunks instead of "v6". I managed to select a range of chunks, and deleted them with self-made script working on the sqlite file. Chunks present within the world are the ones that I wanted to save, but the selections' edges look like this:

Is there any way to fix it?
Edit: The weirdest thing is that I can fly further left, as if the chunks were not there! Looking through map.sqlite shows that there are no chunks on the left. Shouldn't the game regenerate them?

How about using

in the corrupted areas?

If it wouldn't be like 1000000 (yes, a million) chunks to delete - that wouldn't be a problem. As I estimated only about 31000 chunks of over a million should be left intact...
Anyway - I'll try it out.

EDIT: Mentioned command partially does the job - it resets all the nodes in a chunk to air, so it is suitable for emptying corrupted chunks. Sadly they don't get regenerated, which is what I expected.
But the strangest thing is... void chunks got regenerated after I migrated (sic!) from sqlite3 to leveldb, but are somewhat different - now I've got sharply blended biomes (like iced lake neighbouring the desert), where deleteblocks command help.

For me the topic is still open, maybe someone else had simmilar thing in his/her world.