Thank you for your responses, but I'm still seeing no access to sd0.
As I mentioned before, this seems to be a problem with u-boot not initializing
things, but I'm a novice here. That's why I resorted to misc.
On 11/17/25 01:26, Crystal Kolipe wrote:
On Sun, Nov 16, 2025 at 11:03:12PM -0800, Glen Gunsalus wrote:
fdisk sd0 returns nothing as does fdisk /dev/rsd0c.
What do you mean by, 'returns nothing'?
radxa-sd# fdisk /dev/rsd0c
radxa-sd# fdisk sd0
radxa-sd# fdisk rsd0
fdisk: opendev('rsd0', 0x0): No such file or directory
radxa-sd# fdisk /dev/rsd0
fdisk: opendev('/dev/rsd0', 0x0): No such file or directory
radxa-sd#
Now that you are using the correct device names, fdisk should produce output
of some kind.
Doesn't seem to except for No file which is true also on my apu2 boxen.
on all systems ls -l /dev/*sd0* gets rsd0[a-p] and sd0[a-p]
Based on the disklabel output, the kernel sd driver thinks that it is reading
successfully from the eMMC device. Since there is no disklabel on the media,
you get a spoofed disklabel with the correct size information but no
partitions and a duid of 0000000000000000. No I/O errors are returned for
reads. Running disklabel with no options is non-invasive, it doesn't write
to the media.
In that case, I would expect fdisk to return an empty partition table.
From your original message, it seems that the eMMC is not blank but has a
debian installation on it. If you try to read the contents of the eMMC
directly, what do you get?
# dd if=/dev/rsd0c bs=32k | hexdump -C
radxa-sd# dd if=/dev/rsd0c bs=32k | hexdump -C
dd: /dev/rsd0c: Input/output error
0+0 records in
0+0 records out
0 bytes transferred in 0.001 secs (0 bytes/sec)
radxa-sd#
If you're not concerned with preserving the current content of the eMMC, what
happens if you try to write to it using dd?
# dd if=/dev/random of=/dev/sd0c count=1 seek=61554687
radxa-sd# dd if=/dev/random of=/dev/sd0c count=1 seek=61554687dd: /dev/sd0c:
Input/output error
1+0 records in
0+0 records out
0 bytes transferred in 0.000 secs (0 bytes/sec)
radxa-sd#
