Fuse guide: use Wi-Fi and cellular together for big downloads

Fuse lets a large file download inside an app use Wi-Fi and cellular at the same time. Wi-Fi downloads the file from the start while cellular fetches pieces from the end, each link doing a share that matches its speed, and the parts are joined into the exact same file.

Before you start

• A Dopamine rootless jailbreak on iOS 15 or later, with ElleKit and PreferenceLoader. Fuse is tested on iOS 17.1 and 16.3.1; iOS 15 has not been tested yet. Not jailbroken yet? Use the jailbreak finder.
• Fuse is a free beta. It becomes a paid tweak when it leaves beta, but this beta stays free: keep it installed and it keeps working.
• It uses cellular data. It's meant for unlimited plans, and it starts switched off.
• You need Wi-Fi connected and cellular data on at the same time.
• It only speeds up some downloads. Read the next list before you expect a difference.

Which downloads Fuse can speed up

All of these must be true:

• The download happens inside an app while that app is open, using Apple's standard networking. Sileo package downloads are one example.
• The address looks like a file: it ends in a type such as zip, ipa, deb, mp4, mov, mp3, pdf, dmg, iso, 7z, rar, tar, epub or ipsw, or it is a download link.
• The file is at least 1 MB, and the server supports resuming (byte-range requests) and sends it uncompressed.
• Wi-Fi alone would still need more than a few seconds, and cellular is fast enough to add something.

These always stay on one link: Safari downloads, background downloads, App Store installs, apps with their own download engine (such as VLC), and downloads where the app asks not to use cellular data.

Fuse helps most when a single Wi-Fi connection is the bottleneck: slow Wi-Fi, or a server that limits each connection. On fast Wi-Fi, cellular never joins: the download runs at the same speed as without Fuse and uses no cellular data. It can't make a download faster than the server allows overall.

Set it up

1. Add the CarterWare source https://tweaks.carterware.net/ in Sileo or Zebra (how to add a source) and install Fuse.
2. Open Settings → Fuse and turn on Bond downloads.
3. Make sure you're on Wi-Fi and cellular data is on in Control Center.
4. Close and reopen the app you'll download in, then download a large file from a qualifying address.
5. Go back to Settings → Fuse. If cellular helped, Last Bonded Download shows the file's Size and the Links row shows how much came over Wi-Fi and how much over cellular.

Common tasks

Check how much cellular data a download used

Open Settings → Fuse and read Links under Last Bonded Download, for example "28 MB Wi-Fi + 12 MB cellular". The links shown are the ones iOS reports each part actually used.

Stop Fuse from using cellular

Turn off Bond downloads. Open apps pick up the change within a couple of seconds, and every download goes back to the normal single connection.

Settings explained

Every row on Settings → Fuse:

Last Bonded Download

These two rows describe the most recent download where cellular joined in. Size shows the file size and when it finished, or None yet. Links shows how much of the file came over each link. If both parts say Wi-Fi, the cellular part didn't actually travel over cellular for that download.

Troubleshooting

Last Bonded Download still says None yet

Cellular only joins when it can shorten the download, so on fast Wi-Fi nothing is recorded; that's expected. Otherwise, check the list of downloads Fuse can speed up: the app must download in the foreground with standard networking, the file must be 1 MB or larger, and the server must support resuming.

The download isn't any faster

If the server or your Wi-Fi is already fast, cellular stays out on purpose. If cellular is much slower than Wi-Fi, Fuse stops using it after a short try so it doesn't spend data for nothing.

A download fails with Fuse on but works with it off

Turn off Bond downloads, retry to confirm, and send the app name and download address with Report a Bug or the bug form. If the cellular part fails, Fuse fetches the rest over Wi-Fi; if the file changes on the server mid-download, it stops splitting rather than joining two versions.

Questions

Is Fuse free?

Yes, during the beta. Fuse becomes a paid tweak when it leaves beta, but this beta stays free: keep it installed and it keeps working. The paid release will be a separate package.

Does Fuse use cellular data?

Yes. Part of each bonded download comes over cellular, more when cellular is fast. That's why it starts off and why it's meant for unlimited plans.

Does Fuse speed up App Store downloads or Safari?

No. App Store installs, Safari downloads and background downloads happen outside the app, so they stay on one link.

Will Fuse always make downloads faster?

No. It only adds cellular when Wi-Fi alone would take more than a few seconds and cellular can contribute. On fast Wi-Fi the download runs at the same speed as without Fuse, using no cellular data.

Does Fuse keep my sign-ins for downloads that need an account?

Yes. Fuse uses the app's own cookies and saved logins, so downloads that need you to be signed in still work. Links that only work once are left alone.