diff --git a/partitioning/gpt/gpt.go b/partitioning/gpt/gpt.go
index bf7c4ed..5365b14 100644
--- a/partitioning/gpt/gpt.go
+++ b/partitioning/gpt/gpt.go
@@ -558,7 +558,6 @@ func (t *Table) writePMBR() error {
 
 	// boot signature
 	protectiveMBR[510], protectiveMBR[511] = 0x55, 0xAA
-	protectiveMBR[511] = 0xAA
 
 	// PMBR protective entry.
 	b := protectiveMBR[446 : 446+16]
diff --git a/partitioning/gpt/gpt_test.go b/partitioning/gpt/gpt_test.go
index 8b1a7a7..222ee4b 100644
--- a/partitioning/gpt/gpt_test.go
+++ b/partitioning/gpt/gpt_test.go
@@ -138,6 +138,7 @@ func TestGPT(t *testing.T) {
 				)))
 				require.NoError(t, allocateError(table.AllocatePartition(100*MiB, "100M", partType1,
 					gpt.WithUniqueGUID(uuid.MustParse("3D0FE86B-7791-4659-B564-FC49A542866D")),
+					gpt.WithLegacyBIOSBootableAttribute(true),
 				)))
 				require.NoError(t, allocateError(table.AllocatePartition(2.5*GiB, "2.5G", partType2,
 					gpt.WithUniqueGUID(uuid.MustParse("EE1A711E-DE12-4D9F-98FF-672F7AD638F8")),
diff --git a/partitioning/gpt/options.go b/partitioning/gpt/options.go
index fce0091..d49e76c 100644
--- a/partitioning/gpt/options.go
+++ b/partitioning/gpt/options.go
@@ -66,3 +66,12 @@ func WithUniqueGUID(guid uuid.UUID) PartitionOption {
 		o.UniqueGUID = guid
 	}
 }
+
+// WithLegacyBIOSBootableAttribute marks the partition as bootable.
+func WithLegacyBIOSBootableAttribute(val bool) PartitionOption {
+	return func(args *PartitionOptions) {
+		if val {
+			args.Flags |= (1 << 2)
+		}
+	}
+}
diff --git a/partitioning/gpt/testdata/allocate.sfdisk b/partitioning/gpt/testdata/allocate.sfdisk
index 2242f18..a29f37e 100644
--- a/partitioning/gpt/testdata/allocate.sfdisk
+++ b/partitioning/gpt/testdata/allocate.sfdisk
@@ -6,6 +6,6 @@ last-lba: 12582878
 sector-size: 512
 
 start=        2048, size=     2097152, type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, uuid=DA66737E-1ED4-4DDF-B98C-70CEBFE3ADA0, name="1G"
-start=     2099200, size=      204800, type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, uuid=3D0FE86B-7791-4659-B564-FC49A542866D, name="100M"
+start=     2099200, size=      204800, type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, uuid=3D0FE86B-7791-4659-B564-FC49A542866D, name="100M", attrs="LegacyBIOSBootable"
 start=     2304000, size=     5242880, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=EE1A711E-DE12-4D9F-98FF-672F7AD638F8, name="2.5G"
 start=     7546880, size=     2097152, type=E6D6D379-F507-44C2-A23C-238F2A3DF928, uuid=15E609C8-9775-4E86-AF59-8A87E7C03FAB, name="1G"