Fixes bytes convertion method, last episode

This definitely fixes the bytes convertion method.

@lazyhammer thanks for your support & indulgence
@fabpot sorry for the running gag
@vicb I opened a ticket: https://bugs.php.net/bug.php?id=64530

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7481