Date: Thu, 15 Mar 2007 12:11:09 +0100 (CET) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-fs@FreeBSD.ORG, etc@fluffles.net, Dag-Erling =?ISO-8859-1?Q?Sm=F8rgrav?= <des@des.no>, freebsd-bugs@FreeBSD.ORG, freebsd-questions@FreeBSD.ORG Subject: Re: boot2 can't boot from USB? Message-ID: <200703151111.l2FBB9ah006934@lurza.secnetix.de> In-Reply-To: <freebsd-fs.45F91CF0.6010506@fluffles.net>
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Fluffles <etc@fluffles.net> wrote: > Sorry if this is offtopic. Am i right to assume that: > - boot0 and boot1 both read from the disk via BIOS > - boot2 tries to read from the disk directly, without BIOS > ? No, only the kernel contains drivers that are independent from the BIOS. Everything else (the boot* blocks and /boot/loader) use BIOS calls. > If so, i may have found some bugs / problems with boot2. Long ago i > tried to make a bootable USB pendrive with FreeBSD 6.1 on it. It failed > to boot with the message "invalid slice" and i got a prompt like: > > FreeBSD/i386 BOOT > Default: 0:ad(0,a)/boot/loader > boot: > > Whatever i tried, it fails to load "Loader" or the kernel. Later, i > tried FreeNAS which enables the user to write an image to an USB > pendrive which contains a bootable FreeNAS installation. The copying > went ok, but i got the same boot problem. I then tried it on three > different systems with two different USB pendrives and they all had the > same problem. All of the systems supported USB boot, and it does > actually boot from USB how else could i see that FreeBSD boot prompt? > Some systems are brand new: dualcore SLI motherboards, etc. > > It appears to me the boot2 program fails to read from USB. boot0 and > boot1 appear not to have this problem since it uses the BIOS to read > from the disk. Is this correct? No, see above, they all use the BIOS. The difference is that boot2 needs to understand UFS, locate the correct slice and partition with /boot/loader in it and load it. The earlier boot blocks are relatively dumb and only know how to load boot2 from a fixed location on the media. So, if boot2 doesn't work for you, it's probably unable to locate your FreeBSD slice and/or partition. How did you create them? (Another difference is that boot2 enters protected mode in order to be able to access memory above 1 MB, while the earlier boot blocks use pure real mode. But that should not be related to the problem that you see.) > Are USB boot problems by boot2 known, should i file a PR? boot2 doesn't know about USB at all. It only knows about BIOS-accessible drives (which may include USB drives if that's enabled in the BIOS setup). Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd "With sufficient thrust, pigs fly just fine. However, this is not necessarily a good idea. It is hard to be sure where they are going to land, and it could be dangerous sitting under them as they fly overhead." -- RFC 1925
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