diff --git a/bob/devtools/mirror.py b/bob/devtools/mirror.py
index 778ea60a8830d87b9e8ee0617b43b47c79205aae..c83a7b4b474dd374ea157304949f265cb612fe97 100644
--- a/bob/devtools/mirror.py
+++ b/bob/devtools/mirror.py
@@ -325,15 +325,31 @@ def copy_and_clean_json(url, dest_dir, arch, name):
     return _save_json(data, dest_dir, arch, name)
 
 
-def checksum(repodata, basepath, packages):
+def copy_and_clean_patch(url, dest_dir, arch, name):
+    """Copies and cleans conda patch_instructions JSON file"""
+
+    data = get_json(url, arch, name)
+    packages = get_local_contents(dest_dir, arch)
+    data = _cleanup_json(data, packages)
+
+    # cleanup specific patch_instructions.json fields
+    for key in ["remove", "revoke"]:
+        data[key] = [k for k in data[key] if k in packages]
+
+    return _save_json(data, dest_dir, arch, name)
+
+
+def checksum_packages(repodata, dest_dir, arch, packages):
     """Checksums packages on the local mirror and compare to remote repository
 
     Parameters
     ----------
     repodata : dict
         Data loaded from `repodata.json` on the remote repository
-    basepath : str
-        Path leading to the packages in the package list
+    dest_dir : str
+        Path leading to local mirror
+    arch : str
+        Current architecture being considered (e.g. noarch, linux-64 or osx-64)
     packages : list
         List of packages that are available locally, by name
 
@@ -343,11 +359,11 @@ def checksum(repodata, basepath, packages):
         List of matching errors
     """
 
-    issues = []
+    issues = set()
     total = len(packages)
     for k, p in enumerate(packages):
 
-        path_to_package = os.path.join(basepath, p)
+        path_to_package = os.path.join(dest_dir, arch, p)
 
         # checksum to verify
         if p.endswith('.tar.bz2'):
@@ -374,6 +390,6 @@ def checksum(repodata, basepath, packages):
             logger.warning('Checksum of %s does not match remote ' \
                     'repository description (actual:%r != %r:expected)',
                     path_to_package, actual_hash, expected_hash)
-            issues.append(p)
+            issues.add(p)
 
     return issues
diff --git a/bob/devtools/scripts/mirror.py b/bob/devtools/scripts/mirror.py
index 5dded9fb905b5cea50a3fe1db25c3c51c05401a6..8fa1c00b7dea8333ef169e7219734e5a845a789b 100644
--- a/bob/devtools/scripts/mirror.py
+++ b/bob/devtools/scripts/mirror.py
@@ -17,8 +17,8 @@ from ..mirror import (
         whitelist_filter,
         download_packages,
         remove_packages,
-        copy_and_clean_json,
-        checksum,
+        copy_and_clean_patch,
+        checksum_packages,
         )
 from ..log import verbosity_option, get_logger, echo_info, echo_warning
 
@@ -180,8 +180,13 @@ def mirror(
         if checksum:
             # double-check if, among packages I should keep, everything looks
             # already with respect to expected checksums from the remote repo
-            issues = checksum(remote_repodata, os.path.join(dest_dir, arch),
+            issues = checksum_packages(remote_repodata, dest_dir, arch,
                     to_keep)
+            if issues:
+                echo_warning("Detected %d packages with checksum issues - " \
+                        "re-downloading after erasing..." % len(issues))
+            else:
+                echo_info("All local package checksums match expected values")
             remove_packages(issues, dest_dir, arch, dry_run)
             to_download |= issues
 
@@ -206,7 +211,8 @@ def mirror(
             # go crazy.  Do this before the indexing, that will use that file
             # to do its magic.
             patch_file = 'patch_instructions.json'
-            name = copy_and_clean_json(channel_url, dest_dir, arch, patch_file)
+            name = copy_and_clean_patch(channel_url, dest_dir, arch,
+                    patch_file)
             echo_info("Cleaned copy of %s/%s/%s installed at %s" %
                     (channel_url, arch, patch_file, name))