Negative for drives of that "vintage".Any wisdom or guidance on formatting a 4kn SATA drive to 512? I have 4x HGST HUH721010ALN600 10TB SATA 4Kn drives ...
SATA drives conform to the ATA specs, and, unlike SAS drives (SCSI spec), there is no flexibility on format, after manufacture. (The FORMAT TRACK and FORMAT UNIT commands can only duplicate/repeat the format from the factory [512, 512e, 4kn].) However, a couple of new commands were added to ATA, (circa 2016?), to "convert" a 4kn drive (with LBA size=4096) to LBA size=512, and a 512e drive (with 512 LBAs) to 4096 LBAs. I don't know whether this functionality is required, or optional, but it looks like WDC introduced it in HC530 14TB (and some lower capacity drives [e.g., HC310] of that era), and Seagate in the Exos14 series.
Fast-Format is the operative buzzword. I believe this "switch" is accessed via hdparm's --set-sector-size, Hugo's --fastformat, and some tool from Seagate. I don't believe any actual formatting is performed (though all data is lost)--it's probably just a runtime parameter in the firmware.