diff --git a/.github/workflows/scripts/generate-ci-type.py b/.github/workflows/scripts/generate-ci-type.py
index b49255e8381d..08021aabcb61 100755
--- a/.github/workflows/scripts/generate-ci-type.py
+++ b/.github/workflows/scripts/generate-ci-type.py
@@ -1,108 +1,108 @@
 #!/usr/bin/env python3
 
 """
 Determine the CI type based on the change list and commit message.
 
 Prints "quick" if (explicity required by user):
 - the *last* commit message contains 'ZFS-CI-Type: quick'
 or if (heuristics):
 - the files changed are not in the list of specified directories, and
 - all commit messages do not contain 'ZFS-CI-Type: full'
 
 Otherwise prints "full".
 """
 
 import sys
 import subprocess
 import re
 
 """
 Patterns of files that are not considered to trigger full CI.
 Note: not using pathlib.Path.match() because it does not support '**'
 """
 FULL_RUN_IGNORE_REGEX = list(map(re.compile, [
     r'.*\.md',
     r'.*\.gitignore'
 ]))
 
 """
 Patterns of files that are considered to trigger full CI.
 """
 FULL_RUN_REGEX = list(map(re.compile, [
     r'\.github/workflows/scripts/.*',
     r'cmd.*',
     r'configs/.*',
     r'META',
     r'.*\.am',
     r'.*\.m4',
     r'autogen\.sh',
     r'configure\.ac',
     r'copy-builtin',
     r'contrib',
     r'etc',
     r'include',
     r'lib/.*',
     r'module/.*',
     r'scripts/.*',
     r'tests/.*',
     r'udev/.*'
 ]))
 
 if __name__ == '__main__':
 
     prog = sys.argv[0]
 
     if len(sys.argv) != 3:
         print(f'Usage: {prog} <head_ref> <base_ref>')
         sys.exit(1)
 
     head, base = sys.argv[1:3]
 
     def output_type(type, reason):
         print(f'{prog}: will run {type} CI: {reason}', file=sys.stderr)
         print(type)
         sys.exit(0)
 
     # check last (HEAD) commit message
     last_commit_message_raw = subprocess.run([
-        'git', 'show', '-s', '--format=%B', 'HEAD'
+        'git', 'show', '-s', '--format=%B', head
     ], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 
     for line in last_commit_message_raw.stdout.decode().splitlines():
         if line.strip().lower() == 'zfs-ci-type: quick':
             output_type('quick', f'explicitly requested by HEAD commit {head}')
 
     # check all commit messages
     all_commit_message_raw = subprocess.run([
         'git', 'show', '-s',
         '--format=ZFS-CI-Commit: %H%n%B', f'{head}...{base}'
     ], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     all_commit_message = all_commit_message_raw.stdout.decode().splitlines()
 
     commit_ref = head
     for line in all_commit_message:
         if line.startswith('ZFS-CI-Commit:'):
             commit_ref = line.lstrip('ZFS-CI-Commit:').rstrip()
         if line.strip().lower() == 'zfs-ci-type: full':
             output_type('full', f'explicitly requested by commit {commit_ref}')
 
     # check changed files
     changed_files_raw = subprocess.run([
         'git', 'diff', '--name-only', head, base
     ], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     changed_files = changed_files_raw.stdout.decode().splitlines()
 
     for f in changed_files:
         for r in FULL_RUN_IGNORE_REGEX:
             if r.match(f):
                 break
         else:
             for r in FULL_RUN_REGEX:
                 if r.match(f):
                     output_type(
                         'full',
                         f'changed file "{f}" matches pattern "{r.pattern}"'
                         )
 
     # catch-all
     output_type('quick', 'no changed file matches full CI patterns')