I was facing the following problem: AppStore with the latest production build and crashlytics without the corresponding dSYM file needed to symbolicate the crashes.
What to do?

After some investigation, this is what I got from a freshly build dSYM:

  • LC_UUID loads at the beginning of the binary file, with the command 1B.
  • Even if the architecture is litte endian, the UUID are written as big endian. This is a specification of the UUID:
[...]
    /* put name space ID in network byte order so it hashes the same
      no matter what endian machine we're on */
[...]

So:

  1. Go back to the deploy commit, make sure the build system will re-generate the app at the same status.

  2. Archive again, with fastlane’s gym or with a xcarchive

     $ bin/gym # <- (I'm using bundler)

  3. Get the current UUIDs

     $ dwarfdump -u /path/to/MyApp.DSYM
 UUID: EBD9418E-20FF-44C1-8D3F-D7E75CC6F0B1 (armv7) MyApp.dSYM/Contents/Resources/DWARF/MyApp
 UUID: D9936E8B-139E-4F63-A063-7863EEFF6B99 (arm64) MyApp.dSYM/Contents/Resources/DWARF/MyApp

  4. Change the UUIDs of the binary file with a hex editor.
    We are looking for the LC_UUID load command 1B000000 and we know that the command size is a 24 bytes long (or 0x18000000). What is following those bytes is our actual UUID.
    Or 1B000000 18000000 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX, where XXXXXXXX are the bytes you may want change with the correct UUID.

  5. Save, submit, start bugfixing. :tada:

Hex editor