Ubuntu Touch installation guide

[dukla2000]

I would say copying the data is one thing... even for it, dd is not a right tool, you may want to simply copy all files while preserving permissions.

The benefit of dd is that it will duplicate the disk partition layout.

Do you happen to know how the eMMC will be presented? Does one boot the image from the SD card and then run dd from the phone? Or is there a way to mount the device as mass storage on a computer and run dd from there?

Would there be a single partition to write the image to? Because I'm a bit worried to - for instance - overwrite U-Boot or something similar.

No idea on the partition layout: it seems to be release dependant, e.g. on my RockPro64 the ayufan releases use 7 partitions on the disk, 1 for boot,1 for root and 5 others, whereas a Manjaro image implements a single partition.

Yup - I imagine booting from the SDcard then using dd to clone the SDcard (may well be /dev/mmcblk0 as per the RockPro64?) to the eMMC (may well be /dev/mmcblk1 as per theRockPro64?). Will be 1 good reason to have an 8Gb SDcard (or smaller) lying around :-)

Certainly 1 of my arm SBCs has presented the eMMC as a device in a special boot mode, offhand I cannot remember which. I know the Allwinner chips have a FEL mode which seems that it could be useful t get a PinePhone mounted as mass storage though.

Hopefully not too many more days until we can actually answer this stuff definitively!

PS - I just built myself a postmarketOS SDcard using the pmbootstrap script and notice 2 things:
1) pmOS creates 2 partitions on the SDcard, boot & root.
2) The pm bootstrap script already can build your eMMC from your SDcard after booting if you want. See here - postmarketOS may be installed onto the eMMC by running pmbootstrap install --sdcard=/dev/mmcblk... from a Linux distribution booted via the microSD card.