From a6e29467678f17278ff571e833b812e8eb745541 Mon Sep 17 00:00:00 2001
From: alberand <albershteyn.andrey@gmail.com>
Date: Fri, 19 Mar 2021 18:57:49 +0100
Subject: [PATCH] Add BOOT_METHOD variable to control how to generate GRUB2
 config

---
 README.pod |  5 +++++
 novaboot   | 18 ++++++++++++++++--
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/README.pod b/README.pod
index 3472d52..039a1eb 100644
--- a/README.pod
+++ b/README.pod
@@ -931,6 +931,11 @@ The following variables are interpreted in the novaboot script:
 
 =over 8
 
+=item BOOT_METHOD
+
+Specifies the way GRUB2 boots the kernel. For kernels with multiboot
+support use C<multiboot> method (the default). For Linux kernel use C<linux> method.
+
 =item BUILDDIR
 
 Novaboot chdir()s to this directory before file generation phase. The
diff --git a/novaboot b/novaboot
index d6a60ed..abd5b9c 100755
--- a/novaboot
+++ b/novaboot
@@ -575,18 +575,23 @@ sub generate_grub2_config($$$$;$$)
     print $fg "menuentry $title {\n";
     print $fg "$prolog\n" if $prolog;
     my $first = 1;
+    my $boot_method = $variables->{BOOT_METHOD} // "multiboot";
+    my $module_load_method = "module";
+    if ($boot_method eq "linux") {
+	$module_load_method = "initrd";
+    }
     foreach (@$modules_ref) {
 	if ($first) {
 	    $first = 0;
 	    my ($kbin, $kcmd) = split(' ', $_, 2);
 	    $kcmd = '' if !defined $kcmd;
-	    print $fg "  multiboot ${base}$kbin $kcmd\n";
+	    print $fg "  $boot_method ${base}$kbin $kcmd\n";
 	} else {
 	    my @args = split;
 	    # GRUB2 doesn't pass filename in multiboot info so we have to duplicate it here
 	    $_ = join(' ', ($args[0], @args));
 	    s|\brom://|$rom_prefix|g; # We do not need to translate path for GRUB2
-	    print $fg "  module $base$_\n";
+	    print $fg "  $module_load_method $base$_\n";
 	}
     }
     print $fg "}\n";
@@ -1729,6 +1734,10 @@ specified F<grub.cfg> is used. The content of the menu entry can be
 customized with B<--grub-preamble>, B<--grub2-prolog> or
 B<--grub_prefix> options.
 
+GRUB2 can boot multiboot-compliant kernels and a few kernels with specific
+support. L</BOOT_METHOD> could be used to specify the command used by GRUB2 to
+load the kernel. See L<GNU GRUB Manual|https://www.gnu.org/software/grub/manual/grub/grub.html#Booting>.
+
 To use the generated menu entry on your development
 machine that uses GRUB2, append the following snippet to
 F</etc/grub.d/40_custom> file and regenerate your grub configuration,
@@ -2285,6 +2294,11 @@ The following variables are interpreted in the novaboot script:
 
 =over 8
 
+=item BOOT_METHOD
+
+Specifies the way GRUB2 boots the kernel. For kernels with multiboot
+support use C<multiboot> method (the default). For Linux kernel use C<linux> method.
+
 =item BUILDDIR
 
 Novaboot chdir()s to this directory before file generation phase. The
-- 
2.39.2