Failure to complete write to microSD or eMMC

[Jeff Hallam]

I attempted to flash a ".img" file to both a microSD card (via USB adapter) and eMMC (via other USB adapter) using both "dd" and Etcher multiple times. Both programs failed to write the full image to the card/memory but gave no errors. By all appearances the job was completed succesfully. "dd" completed with the normal terminal messages of data transfer rate and amount written. Similarly, Etcher said it was successful. However, using "df" afterwards showed that only ~ 69MB was in use of the ~ 5.8GB image.

- yes, I used "sudo sync" and to be certain "sudo umount /dev/sdb"
- I also tried using the "conv=sync" argument for "dd"

Possibly noteworthy was that the data rate shown by "dd" was impossibly high for USB3.0 (and also for USB2.0 which I also tried). Stated write rates were between ~800MB/s and 1GB/s.

I took a copy of the source image file to a different host running Ubuntu GNOME and was able to successfully complete the exact same process on the first attempt, to the same microSD card. I did not re-attempt the eMMC on the other host.

Not sure that it should matter, but the image was the OS image for the Pinebook:

neon-pinebook-remix-useredition-20190203-1500-arm64-1080p.img

[Jeff Hallam (jeffhallam)]

dmesg output for the microSD card insertion.