Re: gpart destroy efi partition?

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