On Thu, Sep 5, 2024 at 10:51 PM Max Nikulin <maniku...@gmail.com> wrote: > > On 05/09/2024 16:25, Thomas Schmitt wrote: > > I let xorriso-dd-target use > > bs=1M oflag=dsync > > May too small bs value cause write multiplication if internal flash > erasure block size is much larger? I have seen claims that it can be > e.g. 12M > <https://superuser.com/questions/673847/if-i-align-a-partition-to-24mib-then-is-it-also-aligned-to-any-divider-of-this-s> > I have an impression that actual value is not exposed, so it is unknown > to kernel. My concern is wearing, I have no idea if firmware may perform > partial overwrites without apparent impact on speed.
I've run into this situation (more than once)... `dd` fails to write a bootable image with a block size of 1M. But using a block size of 512 results in a bootable image. It used to happen regularly on arm dev boards, like BeagleBoards and CubieTrucks and Wandboards. I don't recall it happening lately. I prefer the larger block size because the image writes faster. But if the board fails to boot, I drop back to 512 to (re)write the image. And I always finish the `dd` command with a `&& sync`. > Are you against "sync" command because it syncs all drives, not the > specific one (besides smooth progress report)? If USB mass storage > driver does not allow to turn port power off before write completion > then it might be a workaround. From my point of view, simple cp > suggested by the install guide is quite reasonable in comparison to dd. > > Another my question is concerning reading of media and -x argument of > isosize. Is it really necessary? I can not figure out what corner cases > are not covered by "head -c BYTES /dev/sdc". Jeff
