Update GRUB test for Secure Boot support

cpuid with the recent Ubuntu GRUB no longer fails,
so instead let's invoke `probe` with an incomplete
command line, which returns fine in SecureBoot
boot environment while it fails in full GRUB
session with an error message.

diff --git a/templates/boot/grub/grmlenv.cfg b/templates/boot/grub/grmlenv.cfg
index fe779ee..ef37872 100644 (file)
--- a/templates/boot/grub/grmlenv.cfg
+++ b/templates/boot/grub/grmlenv.cfg
@@ -1,11 +1,12 @@
 # this is a simple test to identify whether it looks like the Secure Boot enabled/signed
-# GRUB is running or if it's a full featured GRUB version, the former doesn't allow running cpuid
-if cpuid ; then
-  echo "It looks like Secure Boot is NOT enabled."
-  set grml_secureboot=false
-  export grml_secureboot
-else
+# GRUB is running or if it's a full featured GRUB version, the former doesn't
+# fail with invalid usage, while the later will fail with "error: device name required."
+if probe ; then
   echo "It looks like Secure Boot is enabled."
   set grml_secureboot=true
   export grml_secureboot
+else
+  echo "It looks like Secure Boot is NOT enabled."
+  set grml_secureboot=false
+  export grml_secureboot
 fi