Reproduction: Run either of the following on OpenBSD 6.2:
* installboot -r /tmp /dev/null * installboot -r /mnt /dev/sd2c (nothing needs to be mounted on /mnt) These make installboot fail with the error message "installboot: realpath: No such file or directory". Problem: In the context of the ambiguity listed below which comes both from within and without installboot(8), having installboot(8) *say what it thinks is wrong* e.g. a particular file not existing, would be greatly useful. Problem sources: installboot(8) sources of ambiguity: * It seems to me that the underlying technology stack within the OS has some ambiguities in it (per the following definition), e.g. just 10 minutes ago, doing "installboot -v -r /tmp /dev/rsd2c /usr/mdec/biosboot /usr/mdec/boot" with /dev/sd2a mounted on /mnt, FAILED (!!), with the same "installboot: realpath: No such file or directory" failure message. Yet after re-fdisk, re-disklabel, re-newfs sd2a, it *worked*. Yet just before that I had done exactly the same thing, which lead up to the failure, and this was in a virtual machine which is generally safe from uncaught storage errors, so the issue should not have been due to reasons external to the OS. I have had tons of such experiences when doing disk partitioning work, that something works at one time and not at another time. Maybe some cache doesn't get flushed. Maybe OpenBSD delays reloading partitioning tables. So ambiguity in the sense not flushed cache, not documented reload pattern. After >25 hours of work with these tools i can't still really deduce the problem. * Multiple failure states lead to this exact same error message * Producing boot media overall is a fairly monolithic process, sometimes with partially (!) or fully broken extra-OS behavior e.g. broken BIOS or lacking BIOS documentation. * Absence of documentation, e.g. there is presently not a single mentioning of UEFI boot in "man". The realpath() failure message is generated in https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/installboot/util.c?rev=1.11&content-type=text/x-cvsweb-markup . Thanks, Tinker
