diff --git a/gnu/packages/crates-io.scm b/gnu/packages/crates-io.scm
index 8155bd7a94..ff2f9c52ef 100644
--- a/gnu/packages/crates-io.scm
+++ b/gnu/packages/crates-io.scm
@@ -5603,10 +5603,13 @@ values of all the exported APIs match the platform that libc is compiled for.")
       (origin
         (method url-fetch)
         (uri (crate-uri "libgit2-sys" version))
-        (file-name (string-append name "-" version ".crate"))
+        (file-name (string-append name "-" version ".tar.gz"))
         (sha256
          (base32
-          "0l9fvki7qxsl97vgzqwlv75nl213a5vxw7b1jaik97ala356pv6r"))))
+          "0l9fvki7qxsl97vgzqwlv75nl213a5vxw7b1jaik97ala356pv6r"))
+        (modules '((guix build utils)))
+        (snippet
+         '(begin (delete-file-recursively "libgit2") #t))))
     (build-system cargo-build-system)
     (arguments
      `(#:cargo-inputs
@@ -5623,15 +5626,15 @@ values of all the exported APIs match the platform that libc is compiled for.")
            (lambda* (#:key inputs #:allow-other-keys)
              (let ((openssl (assoc-ref inputs "openssl")))
                (setenv "OPENSSL_DIR" openssl))
-             (delete-file-recursively "libgit2")
-             (delete-file-recursively
-               (string-append "guix-vendor/rust-libgit2-sys-"
-                              ,(package-version rust-libgit2-sys-0.10)
-                              ".crate/libgit2"))
-             (delete-file-recursively
-               (string-append "guix-vendor/rust-libz-sys-"
-                              ,(package-version rust-libz-sys-1.0)
-                              ".crate/src/zlib"))
+             ;(delete-file-recursively "libgit2")
+             ;(delete-file-recursively
+             ;  (string-append "guix-vendor/rust-libgit2-sys-"
+             ;                 ,(package-version rust-libgit2-sys-0.10)
+             ;                 ".crate/libgit2"))
+             ;(delete-file-recursively
+             ;  (string-append "guix-vendor/rust-libz-sys-"
+             ;                 ,(package-version rust-libz-sys-1.0)
+             ;                 ".crate/src/zlib"))
              (delete-file-recursively
                (string-append "guix-vendor/rust-libssh2-sys-"
                               ,(package-version rust-libssh2-sys-0.2)
@@ -6591,10 +6594,13 @@ types as proposed in RFC 1158.")
       (origin
         (method url-fetch)
         (uri (crate-uri "libz-sys" version))
-        (file-name (string-append name "-" version ".crate"))
+        (file-name (string-append name "-" version ".tar.gz"))
         (sha256
          (base32
-          "1gjycyl2283525abks98bhxa4r259m617xfm5z52p3p3c8ry9d9f"))))
+          "1gjycyl2283525abks98bhxa4r259m617xfm5z52p3p3c8ry9d9f"))
+        (modules '((guix build utils)))
+        (snippet
+         '(begin (delete-file-recursively "src/zlib") #t))))
     (build-system cargo-build-system)
     (arguments
      `(#:cargo-inputs
@@ -6603,16 +6609,17 @@ types as proposed in RFC 1158.")
         ("rust-cc" ,rust-cc-1.0)
         ("rust-pkg-config" ,rust-pkg-config-0.3)
         ("rust-vcpkg" ,rust-vcpkg-0.2))
-       #:phases
-       (modify-phases %standard-phases
-         (add-after 'configure 'delete-vendored-zlib
-           (lambda _
-             (delete-file-recursively "src/zlib")
-             (delete-file-recursively
-               (string-append "guix-vendor/rust-libz-sys-"
-                              ,(package-version rust-libz-sys-1.0)
-                              ".crate/src/zlib"))
-             #t)))))
+       ;#:phases
+       ;(modify-phases %standard-phases
+       ;  (add-after 'configure 'delete-vendored-zlib
+       ;    (lambda _
+       ;      (delete-file-recursively "src/zlib")
+       ;      (delete-file-recursively
+       ;        (string-append "guix-vendor/rust-libz-sys-"
+       ;                       ,(package-version rust-libz-sys-1.0)
+       ;                       ".crate/src/zlib"))
+       ;      #t)))
+       ))
     (native-inputs
      `(("pkg-config" ,pkg-config)
        ("zlib" ,zlib)))
diff --git a/guix/build/cargo-build-system.scm b/guix/build/cargo-build-system.scm
index 8a8d74ee1b..c2046e5f5a 100644
--- a/guix/build/cargo-build-system.scm
+++ b/guix/build/cargo-build-system.scm
@@ -58,7 +58,7 @@
 (define (crate-src? path)
   "Check if PATH refers to a crate source, namely a gzipped tarball with a
 Cargo.toml file present at its root."
-    (and (gzip-file? path)
+    (and (not (directory-exists? path)) ; not a tarball
          ;; First we print out all file names within the tarball to see if it
          ;; looks like the source of a crate. However, the tarball will include
          ;; an extra path component which we would like to ignore (since we're