Re: How to Copy a Bootable SD card on a Mac
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As David pointed out, specifying the block device itself and not a partition of the device is important. You can double check the available block devices via: sudo fdisk -l??
From the small amount of reading I've done it looks like /dev/rdisk6 is in line with block device naming convention on OSX, but worth?the double check anyways.?
Finally, regarding the progress bar - CTL+t sends the SIGINFO signal to the app running in the current terminal. SIGINFO should cause dd to refresh progress. So just hit CTL+t while its running whenever you want to see an update. (Or, if youre?leery of entering ctl commands on a running process, run 'sudo pkill -INFO -x dd' from another terminal and it should refresh the running instance.
-Leland W7JQP?
[ correction - thanks to Martin on the heads up ]
I'm not a Mac user but a few thoughts:
?? - CORRECTION: Doug's command to write to the new SD card should
*work*.? the fact he put the "of=" directive first confused me but
should work assuming the other points are valid
?????
?? - Is the destination SD card the EXACT same size or LARGER than
the source SD card?? This is a requirement
?? - Is "/dev/rdisk6" the top level device name for the source SD
card or does that also mean some level of partition?? You must ONLY
do the top level device.?
?? - Macs are netorious for adding all kinds of meta data to
things.? As such, I don't recommend to name your dd output as .dmg"
as it's NOT a classic DMG.? Maybe name it ".dd"
After imaging the new card via dd, can you eject and then re-insert
the SD card and mount both partitions?? Were both file systems clean
or did they give errors when trying to mount?? Can you see all files
in both SD card partitions?
--David
KI6ZHD
On 10/18/2023 11:25 AM, Doug Kaye
(K6DRK) wrote:
Thanks, David and David. Still no luck. I tried the
following sequence using both "disk6" and "rdisk6". The resulting
SD cards still won't boot.
¡insert source
SD card
diskutil list
diskutil
unmountDisk /dev/rdisk6
sudo dd
if=/dev/rdisk6 of=SDBackup2.dmg bs=16M conv=fsync
status=progress
diskutil
unmountDisk /dev/rdisk6
¡remove source
and insert destination SD card
diskutil
unmountDisk /dev/rdisk6
sudo dd
of=/dev/rdisk6 if=SDBackup2.dmg bs=16M conv=fsync
status=progress
diskutil
unmountDisk /dev/rdisk6
? ?...doug
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