Date: Sun, 10 Jul 2022 18:34:45 -0300 From: "Dr. Rolf Jansen" <freebsd-rj@cyclaero.com> To: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: Partition layout of ARM SD card images Message-ID: <C1AA808B-8B0F-4D47-A6CE-DF1136787F3F@cyclaero.com> In-Reply-To: <FA446115-E78D-42C9-B5B0-21EF88075FC1@yahoo.com> References: <1F42EED0-B39F-4E33-986A-FB70A3AA4362@cyclaero.com> <FA446115-E78D-42C9-B5B0-21EF88075FC1@yahoo.com>
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> Am 10.07.2022 um 17:48 schrieb Mark Millard <marklmi@yahoo.com>: >=20 > On 2022-Jul-10, at 12:26, Dr. Rolf Jansen <freebsd-rj@cyclaero.com> = wrote: >=20 >> For example let's have a llok on the partition layout of, = FreeBSD-13.1-RELEASE-arm64-aarch64-RPI.img (the others are similar): >>=20 >> # mdconfig -a -u 0 -t vnode -f = diskimg/FreeBSD-13.1-RELEASE-arm64-aarch64-RPI.img >> # gpart show md0 md0s2 >>=20 >> =3D> 63 6291393 md0 MBR (3.0G) >> 63 2016 - free - (1.0M) >> 2079 102312 1 fat32lba [active] (50M) >> 104391 6187041 2 freebsd (3.0G) >> 6291432 24 - free - (12K) >>=20 >> =3D> 0 6187041 md0s2 BSD (3.0G) >> 0 57 - free - (29K) >> 57 6186880 1 freebsd-ufs (2.9G) >> 6186937 104 - free - (52K) >>=20 >> The start of the fat32 boot slice s1 (containing the u-boot) stuff is = neither aligned to 1M nor to 4k, it starts on an odd base. The start of = the BSD payload slice s2 and its size are odd as well. The padding of 57 = blocks within s2 lets the UFS partition start on a globally even base, = namely 104391+57 =3D 104448, which as a matter of fact is 4k aligned = (104448*512/4096 =3D 13056) and 1M aligned as well (104448*512/1024/1024 = =3D 51), however all this keeps looking strange. >>=20 >> Are there reasons for this partition layout besides making it look = more interesting? If yes, some insights would be good. >=20 > The layout details are more specific to the aarch64 RPi* context > than to general aarch64 SD card images. For example, the Rock64 > image is different: >=20 > # mdconfig -a -u 0 -t vnode -f = FreeBSD-14.0-CURRENT-arm64-aarch64-ROCK64-20220708-a0b956f5ac5-256605.img > # gpart show md0 > =3D> 40 6291376 md0 GPT (3.0G) > 40 32728 - free - (16M) > 32768 102400 1 efi (50M) > 135168 6156160 2 freebsd-ufs (2.9G) > 6291328 88 - free - (44K) This is a GPT table, while the others are still MBR. Images which come = with u-boot must have a different layout.=
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