Date: Mon, 22 May 2023 21:35:13 -0700 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Warner Losh <imp@bsdimp.com> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: gpart destroy efi partition? Message-ID: <ZGxCgdOOZHZsKRnh@troutmask.apl.washington.edu> In-Reply-To: <CANCZdfrPwX=1SXnqu4_i0cyt-R38KH8_Jt97PDjRqci0cOXTAw@mail.gmail.com> References: <ZGw2tRM9edxKxXqO@troutmask.apl.washington.edu> <CANCZdfrPwX=1SXnqu4_i0cyt-R38KH8_Jt97PDjRqci0cOXTAw@mail.gmail.com>
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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.washington.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 > > => 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=/dev/zero of=/dev/da0 bs=1m > > 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-fcaa142bc587,0x28,0x3947fb0) 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,WRITEPROTECT> So, I suppose the question is how to clear WRITEPROTECT. -- Steve
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