Date: Tue, 23 May 2023 12:55:21 +0200 From: "Julian H. Stacey" <jhs@berklix.com> To: sgk@troutmask.apl.washington.edu Cc: Warner Losh <imp@bsdimp.com>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: gpart destroy efi partition? Message-ID: <202305231055.34NAtLsE047127@dell.no.berklix.net> In-Reply-To: Your message "Mon, 22 May 2023 21:35:13 -0700." <ZGxCgdOOZHZsKRnh@troutmask.apl.washington.edu>
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Steve Kargl wrote: > On Mon, May 22, 2023 at 09:51:40PM -0600, Warner Losh wrote: > > On Mon, May 22, 2023, 9:45 PM Steve Kargl <sgk@troutmask.apl.washingto= n.edu> > > wrote: > > = > > > Is there a secret incantation for destroying an EFI > > > partition on a USB memstick? After installing FreeBSD, > > > I would like to re-use a memstick, but > > > > > > % gpart destroy da0 > > > gpart: geom 'da0': Read-only file system > > > % gpart destroy -F da0 > > > gpart: geom 'da0': Read-only file system > > > % gpart show da0 > > > =3D> 40 60063664 da0 GPT (29G) > > > 40 60063664 1 ms-basic-data (29G) > > > % gpart delete -i 1 da0 > > > gpart: geom 'da0': Read-only file system > > > % dd if=3D/dev/zero of=3D/dev/da0 bs=3D1m > > > dd: /dev/da0: Read-only file system > > > > > = > > What's mounted? > > = > > Nothing mounted other than the boot partition on > an internal hard drive. I plugged the memstick into > a usb port, and use gpart to list disk info. > > % df > Filesystem 1M-blocks Used Avail Capacity Mounted on > /dev/ada0p2 458231 62032 359539 15% / > devfs 0 0 0 0% /dev > > ada0p1 is the EFI boot partition on the internal drive. > ada0p3 is swap. > > % gpart list da0 > Geom name: da0 > modified: false > state: OK > fwheads: 255 > fwsectors: 63 > last: 60063703 > first: 40 > entries: 128 > scheme: GPT > Providers: > 1. Name: da0p1 > Mediasize: 30752595968 (29G) > Sectorsize: 512 > Stripesize: 0 > Stripeoffset: 20480 > Mode: r0w0e0 > efimedia: HD(1,GPT,a2e07858-a4b6-11ec-ac6a-fcaa142bc587,0x28,0x3947fb= 0) > rawuuid: a2e07858-a4b6-11ec-ac6a-fcaa142bc587 > rawtype: ebd0a0a2-b9e5-4433-87c0-68b6b72699c7 > label: (null) > length: 30752595968 > offset: 20480 > type: ms-basic-data > index: 1 > end: 60063703 > start: 40 > Consumers: > 1. Name: da0 > Mediasize: 30752636928 (29G) > Sectorsize: 512 > Mode: r0w0e0 > > I did find = > > % sysctl -a | grep da01 > kern.geom.disk.da0.flags: 1a8<CANFLUSHCACHE,DIRECTCOMPLETION,CANZONE,WRI= TEPROTECT> > > So, I suppose the question is how to clear WRITEPROTECT. I dont use efi & gpart but some ideas: Why da01 not da0 ? What is da01 ? a typo, or pulling in some gpart kernel stuff ? Is an escalated security level catching you ? I stick to default, on 12.4-rel multi user thats: sysctl -a | grep level # kern.securelevel: -= 1 Try a fresh reboot, even staying single user, & before you touch it with any gpart invoking command, whack it with multiple dd if=3D/dev/zero of=3D/dev/zero count=3D5000 (multiple as sometimes Ive seen first attempt doesnt seem to clear my sticks, a 2nd reboot after dd will clear any false cached memories) If that doesnt work: Try an older BSD that does know about EFI & gpart ? Put it a Microsoft PC, or a USB to Go adapter on an android, that probbly will complain unknown & offer to bash it back to MBR ? Rumage around or ask friends, eg I have a tiny old match box size thing that clones sticks. Clone your stick from some other small stick, then repair the wrong sized MBR Cheers, -- = Julian Stacey www.StolenVotes.UK/jhs/ Arm Ukraine, Zap Putin. Brexit infl= ates http://berklix.org/ferries/#dover_solution
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