The resize_root script wouldn't do anything if the fdisk and disklabel aren't adjusted (provided it's not a raw filesystem file that's being resized as in http:

The resize_root script wouldn't do anything if the fdisk and disklabel aren't adjusted (provided it's not a raw filesystem file that's being resized as in http://wiki.netbsd.org/amazon_ec2/build_your_own_ami/ http://wiki.netbsd.org/amazon_ec2/build_your_own_ami/ page), so it's kind of expected that it doesn't work all by itself, and that https://git.sr.ht/~sircmpwn/builds.sr.ht/tree/master/images/netbsd/genimg https://git.sr.ht/~sircmpwn/builds.sr.ht/tree/master/images/... is wrong.