PBP Backups (and newbie intro)

[Syonyk]

First, I need to choose a linux distro which I can boot from SDcard.  Then insert a 64GB USB thumbdrive.  Boot the SDcard image.  finally dd the emmc to the USB.  poweroff, eject media and boot back to normal.    To restore, I do the above but dd the other way from USB to EMMC.

Is this a sound strategy or does it take me down a more aggravating path than one I'm not aware of, yet?

That will work fine. I might toss gzip compression in the path to reduce the data written, but what you propose will work, as long as the usable space on the USB drive is sufficient to store the full image.

There's e2image that will work for the root filesystem (if it's ext series) by only copying used blocks, which might be nice, but you'll want full partition backups of anything containing the uboot binaries, because some OSes are... a bit creative in how they handle that.

For general messing around, though, the PBP should preferentially boot the SD card over the eMMC. So keep something usable on eMMC, mess around on the SD card. Performance isn't great, but for messing around, it's fine.

And where exactly does etcher come into play?  Burning the OS to the SDcard?

Etcher is a convenient GUI for writing out images to SD cards, though I've seen it complain about some of the community images. I just use dd.