Mildly pedantic, and of course ignores how wild this whole thing is, but I don't think this bit is correct: After waiting for a little while, the program ter

Mildly pedantic, and of course ignores how wild this whole thing is, but I don't think this bit is correct: After waiting for a little while, the program terminated with the following output: astrid@chungus infra gzip -vc result/nixos.img | ssh root@myhost.example -- bash -c 'gunzip -vc > /dev/sda' root@myhost.example's password: 77.8% -- replaced with stdout What happened here? The 77.8% bit is gunzip -v reporting that it finished decompressing the data to stdout and that the compression ratio was 77.8%... so this invocation may well have succeeded. Assuming, as rwmj points out, nothing else stomped on any of the written blocks. I do like this idea - with sufficient prep of the system before writing the image, namely stopping as many processes as possible especially those that might do some writing, it's a quick and dirty way to replace a stock OS with a ready-made image. Could perhaps be safer doing it twice, once into a minimal image that does very little beyond network bringup & runs ssh, followed by final OS replacement in a (more) controlled manner.