The spotify repository is ass. Randomly breaks on downloading, and sometimes eopkg is too stupid to realize it and checks the hash of the incomplete download.
Guess I'll switch to the other URL again, though that didn't work well for other people.
edit: Done. While the https download seems to cut out more often, it always succesfully retries (for me at least). If you have very slow download speeds you might have to adjust the --retry-attempts
eopkg
parameter to something higher than the default 5.