By now, guix reconfigure has tried to download the same texlive binary from hydra at least 5 times to the same machine, unsuccessfully breaking after about 1 GB each, for a total of 5 GB, always starting from the beginning.
Would it be possible to just resume?
Additionally, it doesn't seem like it checks the Content-Length in order to find out whether the connection broke before the file was done. Why doesn't it?
The http-client seems to handle chunked encoding - so not sure whether it's a problem with hydra or with guix.