diff --git a/metropolis/pkg/gpt/linux_test.go b/metropolis/pkg/gpt/linux_test.go
index 19ac519..7f7f6de 100644
--- a/metropolis/pkg/gpt/linux_test.go
+++ b/metropolis/pkg/gpt/linux_test.go
@@ -5,7 +5,8 @@
 	"testing"
 
 	"github.com/google/uuid"
-	"golang.org/x/sys/unix"
+
+	"source.monogon.dev/metropolis/pkg/blockdev"
 )
 
 var testUUID = uuid.MustParse("85c0b60f-caf9-40dd-86fa-f8797e26238d")
@@ -14,15 +15,13 @@
 	if os.Getenv("IN_KTEST") != "true" {
 		t.Skip("Not in ktest")
 	}
-	ram0, err := os.OpenFile("/dev/ram0", os.O_RDWR, 0)
+	ram0, err := blockdev.Open("/dev/ram0")
 	if err != nil {
 		panic(err)
 	}
 	g := Table{
-		ID:         uuid.NewSHA1(testUUID, []byte("test")),
-		BlockSize:  512,
-		BlockCount: 2048,
-		BootCode:   []byte("just some test code"),
+		ID:       uuid.NewSHA1(testUUID, []byte("test")),
+		BootCode: []byte("just some test code"),
 		Partitions: []*Partition{
 			nil,
 			// This emoji is very complex and exercises UTF16 surrogate encoding
@@ -31,13 +30,13 @@
 			nil,
 			{Name: "Test2", FirstBlock: 20, LastBlock: 49, Type: PartitionTypeEFISystem, ID: uuid.NewSHA1(testUUID, []byte("test2")), Attributes: 0},
 		},
+		b: ram0,
 	}
-	if err := Write(ram0, &g); err != nil {
+	if err := g.Write(); err != nil {
 		t.Fatalf("Failed to write GPT: %v", err)
 	}
-
-	if err := unix.IoctlSetInt(int(ram0.Fd()), unix.BLKRRPART, 0); err != nil {
-		t.Fatalf("Failed to reread partition table: %v", err)
+	if err := ram0.RefreshPartitionTable(); err != nil {
+		t.Fatalf("Failed to refresh partition table: %v", err)
 	}
 	if _, err := os.Stat("/sys/block/ram0/ram0p2"); err != nil {
 		t.Errorf("Expected ram0p2 to exist, got %v", err)