diff --git a/nixos/modules/system/boot/loader/limine/limine-install.py b/nixos/modules/system/boot/loader/limine/limine-install.py
index 96a5b999d5fc..6991235539d8 100644
--- a/nixos/modules/system/boot/loader/limine/limine-install.py
+++ b/nixos/modules/system/boot/loader/limine/limine-install.py
@@ -395,7 +395,7 @@ def main():
             limine_deploy_args = [limine_binary, 'bios-install', device]
 
         if config('partitionIndex'):
-            limine_deploy_args.append(config('partitionIndex'))
+            limine_deploy_args.append(str(config('partitionIndex')))
 
         if config('forceMbr'):
             limine_deploy_args += '--force-mbr'