diff --git a/mxgrub/mxgrub b/mxgrub/mxgrub
index ec0f0be..a5fe017 100755
--- a/mxgrub/mxgrub
+++ b/mxgrub/mxgrub
@@ -12,6 +12,7 @@ sub USAGE { return <<"EOF" }
     $0 --initramfs : update /boot/grub/initramfs.igz from /project/admin/initramfs
     $0 --test      : perform miscellaneous tests (VX50 board)
     $0 --reboot    : attempt kexec reboot of selected kernel
+    $0 --set-default {label} : select this kernel as the default kernel
 EOF
 
 sub sys {
@@ -322,18 +323,18 @@ sub cmd_install {
 	update_grub_cfg();
 
 	if (has_esp) {
-		sys 'mount','-L','ESP','/boot/efi' and exit 1;
+		sys 'mount','-L','ESP','/boot/efi';
 		if (-d '/boot/efi/EFI/grub/grubx64.efi') {
 			print "GRUB for UEFI is already installed.\n";
 		}
 		else {
-			sys 'grub-install','--target=x86_64-efi','--no-nvram',$root_disk and exit 1;
+			sys 'grub-install','--target=x86_64-efi','--no-nvram',$root_disk;
 		}
-		sys 'umount','/boot/efi' and exit 1;
+		sys 'umount','/boot/efi';
 	}
 
 	if ($mbr_type ne 'GRUB') {
-		sys 'grub-install','--target=i386-pc',$root_disk and exit 1;
+		sys 'grub-install','--target=i386-pc',$root_disk;
 	} else {
 		print "GRUB is already installed in MBR.\n";
 	}
@@ -352,7 +353,7 @@ sub cmd_update {
 }
 
 sub cmd_initramfs {
-	sys('bash','-c','cd /project/admin/initramfs;find .|cpio -H newc -o | gzip > /boot/grub/initramfs.igz');
+	sys('bash','-c','cd /project/admin/initramfs ; find . -name ".git*" -prune -or -print | cpio -H newc -o | gzip > /boot/grub/initramfs.igz');
 }
 
 sub cmd_reboot {
@@ -363,10 +364,19 @@ sub cmd_reboot {
 	sys('kexec',"/boot/$image",'--initrd=/boot/grub/initramfs.igz',"--command-line=root=LABEL=root $KERNEL_PARAMETER");
 }
 
+sub cmd_set_default {
+	my ($label)=@_;
+	my $image=label_to_image($label);
+	-e "/boot/$image" or die "/boot/$image: no such file\n";
+	sys 'ln','-sf',$image,'/boot/bzImage.x86_64';
+	scan_mariux(0);
+	update_grub_cfg();
+}
+
 umask 022;
 check_grub_installation();
 
-our ($opt_list,$opt_update,$opt_initramfs,$opt_test,$opt_reboot);
+our ($opt_list,$opt_update,$opt_initramfs,$opt_test,$opt_reboot,$opt_set_default);
 
 GetOptions(
 		'list'      => \$opt_list,
@@ -374,6 +384,7 @@ GetOptions(
 		'initramfs' => \$opt_initramfs,
 		'test'      => \$opt_test,
 		'reboot'    => \$opt_reboot,
+		'set-default' => \$opt_set_default,
 
 ) or die USAGE;
 
@@ -407,6 +418,9 @@ if ($opt_list) {
 } elsif ($opt_reboot) {
 	@ARGV==0 or die USAGE;
 	cmd_reboot();
+} elsif ($opt_set_default) {
+	@ARGV==1 or die USAGE;
+	cmd_set_default($ARGV[0]);
 } else {
 	@ARGV==1 or die USAGE;
 	cmd_install($ARGV[0]);