The bit about disk drive lying about syncing writes is a persistent myth. There have probably been some HDDs at some point which had notable bugs in their flush

The bit about disk drive lying about syncing writes is a persistent myth. There have probably been some HDDs at some point which had notable bugs in their flush command, but in general drives do actually write data to disk before reporting complete status for a flush. I spent several years working for a major HDD manufacturer and their firmware QA process included a test rig which would repeatedly pull power to the drive while sending write and flush commands. The drive would then be powered up and the data on the drive examined to verify that all data which should have been flushed actually made it to disk. I think this myth persists mostly because it can be surprising difficult to coax an OS into sending a flush command for much the same reason disk drives get accused of lying about it: performance. These days the most reliably solution is to reconfigure the drive with write caching disabled. This way the drive will ensure every write hits the disk before reporting completion to the host. Write caching remains enabled by default on SATA drives mostly for historical reasons. Back before command queuing was commonly supported write caching gave a large speedup. These days everything supports NCQ so disabling write caching only has a small performance impact.