This is how you flash to eMMC easily

[Zebulon Walton]

Sounds like bufferbloat at work.  (Data quickly fills buffers then I/O slows down writing to the slow physical device.) However that shouldn't cause your restore to take over 5 hours.

I add "conv=fsync" to the dd command line to make sure data is flushed to the device before dd exits. When using a large buffer this can also help catch errors that might otherwise go unreported:

https://abbbi.github.io/dd/

As an aside, to save some disk space I pipe the image backup through gzip. If the pinephone is /dev/sdc this would be:

Code:

dd if=/dev/sdc bs=1M status=progress conv=fsync | gzip -c >pinephone.img.gz

To restore:

Code:

gunzip -c pinephone.img.gz | dd of=/dev/sdc bs=1M status=progress conv=fsync