Could not perform backup protocol version exchange, error code -1

Question

I need to backup iphone with libimobiledevice, using ubuntu, the device is detected but going to launch the backup commands the following error is displayed:

Started "com.apple.mobilebackup2" service on port 49343. Could not perform backup protocol version exchange, error code -1

What could it depend on?

Answer 1

Several Github issues have reported this problem, like this one.

Solution:

you need to use latest version of idevicebackup and libimobiledevice

Indeed, if you use Ubuntu 20.04 (for instance), the libimobiledevice package is outdated, as of now.

If that's your case, you'll have to either wait for the next Ubuntu release (22.04) or compile it from source, what may become necessary at some point after the release of Ubuntu 22.04 anyway.

Disclaimer: downside of compiling yourself is that your binaries are not managed by the package manager. You'll have to update yourself, git pulling or downloading the newest source code releases and re-compiling everything everytime. You might have to redo all of this after a distribution upgrade. Upside is that your binaries do work...

Note: compilation steps are described on the official site only for debian; I could perform them equally well on a Linux Mint 20.3 (based on Ubuntu, based on debian). OP does not mention the OS he or she uses, but debian based seem to be the only ones available for now, so what follows should work on debian based OSes.

Compilation from source, step by step:

• uninstall the official package and its dependencies and:

• install the build dependencies: sudo apt install build-essential checkinstall git autoconf automake libtool-bin libplist-dev libusbmuxd-dev libssl-dev usbmuxd (see "from source" here)

• get libimobiledevice source code from its repo, using for instance git clone https://github.com/libimobiledevice/libimobiledevice.git. You might get to the releases page and use the latest tar.gz instead (1.3 at the moment).

• also get source code of other libraries required by libimobiledevice: libplist, libimobiledevice-glue and libusbmuxd. (I also compiled usbmuxd instead of using the official package, but I am not sure it is necessary). For each one of them, you can git clone it or download and untar the latest source code release, if available.

• choose a prefix directory, where libraries and binaries will go. Create it if necessary (official libimobiledevice site suggests /opt/local and I will use this too in the next steps; in order for the compilation to work, you'll have to sudo mkdir /opt/local and export PKG_CONFIG_PATH=/opt/local/lib/pkgconfig before starting the first compilation)

• to compile and install, cd to the root of each git-cloned (or source-downloaded) directory (in this order: lipblist, libimobiledevice-glue, libusbmuxd and libimobiledevice, because each one depends on the previous one) and execute, in each one of them: ./autogen.sh --prefix=/opt/local, then make and finally sudo make install. (Note, the autogen line for libimobiledevice may be ./autogen.sh --prefix=/opt/local --enable-debug, as suggested here).

Having done all of this, the iphone was not mounted automatically, I had to manually run idevicepair pair and then could mount it using ifuse ./iphone_mount_point/ (do sudo apt install ifuse if necessary) and perform a backup using idevicebackup2 backup --full iphone_backup/. Read the help of idevicebackup2 for more information.