Balena Etcher Pro- Request Decompress zstandard compressed images on the fly?

I have bought a balena etcher pro (its very nice) and was wondering if a feature to do 3 things:

  1. read .zst files (zstandard compressed images!)
  2. read ‘map’ files from things like bmaptool to make burns faster?

Would be great, otherwise a great product.


Also noticed that the ssh port is 22222. Would be fun to hack a bit!

Hello @symgryph welcome to the balena community! And happy that balena Etcher Pro works great for you!

I attached the github issue about adding zstd support on Etcher. I saw that you actually commented on it. Not sure there is any priority on this, but I will ping the Etcher team to know more.

We are happy to see how you hack the ssh port :slight_smile:

Keep us updated on this!

Does the balena support any kind of compressed? Xz, gzip blah? I could just use one of the supported ones for writing from the network……IT does look like you are using public keys, so I suspect the ssh port is probably safe. I will try some of the stupidisms that most people do like root/root blah, and maybe a few days of hydra to see if password auth is turned on.


read .zst files (zstandard compressed images!)
Does the balena support any kind of compressed? Xz, gzip blah?

Hi, we currently support zip, bz2, gz, and xz, but not zstd (in fact, this is the first time I’m hearing about it), but I will make a not of it for a future release.

read ‘map’ files from things like bmaptool to make burns faster?

We actually do something similar to this by trimming partitions (punching holes in the disk image) with a tool we developed, which is part of what makes Etcher so fast!

Thanks for your suggestions…happy hacking!

Actually Etcher’s version is better, because we don’t require the image to already have be a sparse file

How do I utilize this feature? I would like to have ‘master’ images that have magic in them. I am using an f2fs partition which seems to default to ‘dumb copy block mode’ the entire disk is zeroed out (prior to imaging), but still does the entire 32gb partitsions.

Hmm, yes, Etcher only trims ext4 partitions, but support is planned in the future for other file systems. So, for right now, Etcher will copy everything as though it were a regular file, which means it will still copy the 0’s for the empty blocks, even with a sparse image (although that will hopefully change soon).

For your use case, I would just use:

dd of=myusb.img if=/dev/sdb conv=sparse bs=512

rather than etcher, although check back in the future, we have great things planned!

Ok, actually my above command won’t work…I created a work around though with a gnu tar hack:

tar -cv -O --sparse INPUT_FILE_NAME | sudo tar -xv --sparse --transform s/INPUT_FILE_NAME/OUTPUT_DISK/

So, you can use that if you want until we support it in Etcher.