diff --git a/go.mod b/go.mod
index 72453f7..74c5073 100644
--- a/go.mod
+++ b/go.mod
@@ -5,6 +5,6 @@ module wa-lang.org/wa
 go 1.17
 
 require (
-	github.com/tetratelabs/wazero v1.0.0-pre.4
+	github.com/tetratelabs/wazero v1.0.1
 	wa-lang.org/wabt-go v1.2.3
 )
diff --git a/go.sum b/go.sum
index 54d3eff..507c42a 100644
--- a/go.sum
+++ b/go.sum
@@ -1,4 +1,4 @@
-github.com/tetratelabs/wazero v1.0.0-pre.4 h1:RBJQT5OzmORkSp6MmZDWoFEr0zXjk4pmvMKAdeUnsaI=
-github.com/tetratelabs/wazero v1.0.0-pre.4/go.mod h1:u8wrFmpdrykiFK0DFPiFm5a4+0RzsdmXYVtijBKqUVo=
+github.com/tetratelabs/wazero v1.0.1 h1:xyWBoGyMjYekG3mEQ/W7xm9E05S89kJ/at696d/9yuc=
+github.com/tetratelabs/wazero v1.0.1/go.mod h1:wYx2gNRg8/WihJfSDxA1TIL8H+GkfLYm+bIfbblu9VQ=
 wa-lang.org/wabt-go v1.2.3 h1:xwGW3+IrCMAPDx+ngQFx7vl0xBc1vuooRNql7i2yCiA=
 wa-lang.org/wabt-go v1.2.3/go.mod h1:v4fKY/p4oMiKwQ2S2aC/wOXvJ2bk2MgtLmwK0TKTNx0=
diff --git a/internal/app/waruntime/arduino.go b/internal/app/waruntime/arduino.go
index 9fd8de7..aa53e66 100644
--- a/internal/app/waruntime/arduino.go
+++ b/internal/app/waruntime/arduino.go
@@ -63,10 +63,10 @@ func ArduinoInstantiate(ctx context.Context, rt wazero.Runtime) (api.Closer, err
 		Export("getPinLED").
 		NewFunctionBuilder().
 		WithFunc(func(ctx context.Context, m api.Module, ptr, len uint32) {
-			bytes, _ := m.Memory().Read(ctx, ptr, len)
+			bytes, _ := m.Memory().Read(ptr, len)
 			fmt.Printf("arduino.print(%q)\n", string(bytes))
 		}).
 		WithParameterNames("ptr", "len").
 		Export("print").
-		Instantiate(ctx, rt)
+		Instantiate(ctx)
 }
diff --git a/internal/app/waruntime/chrome.go b/internal/app/waruntime/chrome.go
index e755f32..ac2c266 100644
--- a/internal/app/waruntime/chrome.go
+++ b/internal/app/waruntime/chrome.go
@@ -11,5 +11,5 @@ import (
 )
 
 func ChromeInstantiate(ctx context.Context, rt wazero.Runtime) (api.Closer, error) {
-	return rt.NewHostModuleBuilder(config.WaOS_chrome).Instantiate(ctx, rt)
+	return rt.NewHostModuleBuilder(config.WaOS_chrome).Instantiate(ctx)
 }
diff --git a/internal/app/waruntime/wasi.go b/internal/app/waruntime/wasi.go
index dcade2a..acb4100 100644
--- a/internal/app/waruntime/wasi.go
+++ b/internal/app/waruntime/wasi.go
@@ -29,7 +29,7 @@ func WasiInstantiate(ctx context.Context, rt wazero.Runtime) (api.Closer, error)
 		// ----
 		NewFunctionBuilder().
 		WithFunc(func(ctx context.Context, m api.Module, pos, len uint32) {
-			bytes, _ := m.Memory().Read(ctx, pos, len)
+			bytes, _ := m.Memory().Read(pos, len)
 			fmt.Print(string(bytes))
 		}).
 		WithParameterNames("pos", "len").
@@ -46,44 +46,58 @@ func WasiInstantiate(ctx context.Context, rt wazero.Runtime) (api.Closer, error)
 		}).
 		WithParameterNames("ch").
 		Export("waPrintRune").
-		Instantiate(ctx, rt)
+		Instantiate(ctx)
 }
 
-func wasi_fdWriteFn(ctx context.Context, mod api.Module, fd, iovs, iovsCount, resultSize uint32) wasi.Errno {
+// errno is neither uint16 nor an alias for parity with wasm.ValueType.
+type errno = uint32
+
+const (
+	// ErrnoSuccess No error occurred. System call completed successfully.
+	errnoSuccess errno = 0
+
+	// errnoFault Bad address.
+	errnoFault errno = 21
+
+	// errnoIo I/O error.
+	errnoIo errno = 29
+)
+
+func wasi_fdWriteFn(ctx context.Context, mod api.Module, fd, iovs, iovsCount, resultSize uint32) errno {
 	var err error
 	var nwritten uint32
 	var writer = os.Stdout
 
 	for i := uint32(0); i < iovsCount; i++ {
 		iov := iovs + i*8
-		offset, ok := mod.Memory().ReadUint32Le(ctx, iov)
+		offset, ok := mod.Memory().ReadUint32Le(iov)
 		if !ok {
-			return wasi.ErrnoFault
+			return errnoFault
 		}
 		// Note: emscripten has been known to write zero length iovec. However,
 		// it is not common in other compilers, so we don't optimize for it.
-		l, ok := mod.Memory().ReadUint32Le(ctx, iov+4)
+		l, ok := mod.Memory().ReadUint32Le(iov + 4)
 		if !ok {
-			return wasi.ErrnoFault
+			return errnoFault
 		}
 
 		var n int
 		if writer == io.Discard { // special-case default
 			n = int(l)
 		} else {
-			b, ok := mod.Memory().Read(ctx, offset, l)
+			b, ok := mod.Memory().Read(offset, l)
 			if !ok {
-				return wasi.ErrnoFault
+				return errnoFault
 			}
 			n, err = writer.Write(b)
 			if err != nil {
-				return wasi.ErrnoIo
+				return errnoIo
 			}
 		}
 		nwritten += uint32(n)
 	}
-	if !mod.Memory().WriteUint32Le(ctx, resultSize, nwritten) {
-		return wasi.ErrnoFault
+	if !mod.Memory().WriteUint32Le(resultSize, nwritten) {
+		return errnoFault
 	}
-	return wasi.ErrnoSuccess
+	return errnoSuccess
 }