diff --git a/psf-memo-client/acceptance/lib/handlers.js b/psf-memo-client/acceptance/lib/handlers.js
index 6637243..c8fdbf2 100644
--- a/psf-memo-client/acceptance/lib/handlers.js
+++ b/psf-memo-client/acceptance/lib/handlers.js
@@ -98,8 +98,12 @@ function makeWallet (address) {
       return this.utxos
     },
     sendOpReturn: async function (msg, prefix, bchOutput = []) {
-      // Record the broadcast attempt, then fail if configured to do so.
-      this.broadcasts.push({ msg, prefix, bchOutput })
+      // Normalize binary payloads to Buffer so assertions can safely use
+      // toString('hex'), while preserving string payloads unchanged.
+      const storedMsg = (msg instanceof Uint8Array || ArrayBuffer.isView(msg))
+        ? Buffer.from(msg)
+        : msg
+      this.broadcasts.push({ msg: storedMsg, prefix, bchOutput })
       if (this.failWith) throw new Error(this.failWith)
       return 'aa'.repeat(32)
     }
@@ -1751,6 +1755,38 @@ const handlers = [
       }
     }
   },
+  {
+    name: 'broadcasts OP_RETURN with Memo binary hash160 payload for address',
+    pattern: /^the app broadcasts an OP_RETURN transaction with the Memo (follow|unfollow|mute|unmute) prefix and the binary hash160 payload for the address (.+)$/,
+    run (m, example, world) {
+      const action = m[1]
+      const addr = resolveParam(m[2], example)
+      const hash160 = world.wallet.bchjs.Address.toHash160(addr)
+      const prefix = {
+        follow: MEMO_FOLLOW_PREFIX,
+        unfollow: MEMO_UNFOLLOW_PREFIX,
+        mute: MEMO_MUTE_PREFIX,
+        unmute: MEMO_UNMUTE_PREFIX
+      }[action]
+      if (!prefix) {
+        throw new Error(`Unknown follow/mute action: ${action}`)
+      }
+      const broadcasts = world.wallet.broadcasts
+      if (!broadcasts.length) {
+        throw new Error('No OP_RETURN transaction was broadcast.')
+      }
+      const last = broadcasts[broadcasts.length - 1]
+      if (last.prefix !== prefix) {
+        throw new Error(`Expected Memo ${action} prefix ${prefix}, got "${last.prefix}".`)
+      }
+      if (last.msg.length !== 20) {
+        throw new Error(`Broadcast ${action} payload is not 20 bytes.`)
+      }
+      if (last.msg.toString('hex') !== hash160) {
+        throw new Error(`Broadcast ${action} hash160 did not match ${addr}.`)
+      }
+    }
+  },
   {
     name: 'API serves topic with post count',
     pattern: /^the psf-memo-db API serves a topic named "([^"]+)" with (\d+) posts?$/,
diff --git a/psf-memo-client/src/services/memo-follow.js b/psf-memo-client/src/services/memo-follow.js
index 381f14f..05f2afe 100644
--- a/psf-memo-client/src/services/memo-follow.js
+++ b/psf-memo-client/src/services/memo-follow.js
@@ -17,6 +17,7 @@
 */
 
 const MemoAction = require('./memo-action')
+const { hexToBytes } = require('./hex')
 
 const MEMO_FOLLOW_PREFIX = '6d06'
 const MEMO_UNFOLLOW_PREFIX = '6d07'
@@ -78,7 +79,7 @@ class MemoFollow extends MemoAction {
     await this.wallet.getUtxos()
 
     const hash160 = this._toHash160(followeeAddr)
-    const raw = Buffer.from(hash160, 'hex')
+    const raw = hexToBytes(hash160, PK_HASH_LENGTH, 'Address hash160')
 
     const txid = await this.wallet.sendOpReturn(raw, prefix)
 
diff --git a/psf-memo-client/src/services/memo-mute.js b/psf-memo-client/src/services/memo-mute.js
index 892a796..0fda779 100644
--- a/psf-memo-client/src/services/memo-mute.js
+++ b/psf-memo-client/src/services/memo-mute.js
@@ -17,6 +17,7 @@
 */
 
 const MemoAction = require('./memo-action')
+const { hexToBytes } = require('./hex')
 
 const MEMO_MUTE_PREFIX = '6d16'
 const MEMO_UNMUTE_PREFIX = '6d17'
@@ -78,7 +79,7 @@ class MemoMute extends MemoAction {
     await this.wallet.getUtxos()
 
     const hash160 = this._toHash160(muteeAddr)
-    const raw = Buffer.from(hash160, 'hex')
+    const raw = hexToBytes(hash160, PK_HASH_LENGTH, 'Address hash160')
 
     const txid = await this.wallet.sendOpReturn(raw, prefix)
 
diff --git a/psf-memo-client/test/property/follow.property.test.js b/psf-memo-client/test/property/follow.property.test.js
index b795192..90000d3 100644
--- a/psf-memo-client/test/property/follow.property.test.js
+++ b/psf-memo-client/test/property/follow.property.test.js
@@ -24,6 +24,10 @@ const rng = seededRandom(20260830)
 const MY_ADDRESS = 'bitcoincash:qqlrzp23w08434twmvr4fxw672whkjy0py26r63g3d'
 const CHARS = 'qpzry9x8gf2tvdw0s3jn54khce6mua7l'
 
+function broadcastHex (wallet, index = 0) {
+  return Buffer.from(wallet.broadcasts[index].msg).toString('hex')
+}
+
 // Deterministic 20-byte hash160 hex for any input string, mirroring what a
 // real wallet's bch-js produces for a valid cash address.
 function hash20 (s) {
@@ -86,9 +90,9 @@ test('follow broadcasts exactly one hash160 payload with the follow prefix', asy
 
       return wallet.broadcasts.length === 1 &&
         wallet.broadcasts[0].prefix === MemoFollow.MEMO_FOLLOW_PREFIX &&
-        Buffer.isBuffer(wallet.broadcasts[0].msg) &&
+        wallet.broadcasts[0].msg instanceof Uint8Array &&
         wallet.broadcasts[0].msg.length === MemoFollow.PK_HASH_LENGTH &&
-        wallet.broadcasts[0].msg.toString('hex') === hash20(addr)
+        broadcastHex(wallet, 0) === hash20(addr)
     },
     { label: 'follow broadcast conservation and hash160 length' }
   )
@@ -104,9 +108,9 @@ test('unfollow broadcasts exactly one hash160 payload with the unfollow prefix',
 
       return wallet.broadcasts.length === 1 &&
         wallet.broadcasts[0].prefix === MemoFollow.MEMO_UNFOLLOW_PREFIX &&
-        Buffer.isBuffer(wallet.broadcasts[0].msg) &&
+        wallet.broadcasts[0].msg instanceof Uint8Array &&
         wallet.broadcasts[0].msg.length === MemoFollow.PK_HASH_LENGTH &&
-        wallet.broadcasts[0].msg.toString('hex') === hash20(addr)
+        broadcastHex(wallet, 0) === hash20(addr)
     },
     { label: 'unfollow broadcast conservation and hash160 length' }
   )
diff --git a/psf-memo-client/test/property/mute-services.property.test.js b/psf-memo-client/test/property/mute-services.property.test.js
index 65f6f3e..e9b557d 100644
--- a/psf-memo-client/test/property/mute-services.property.test.js
+++ b/psf-memo-client/test/property/mute-services.property.test.js
@@ -24,6 +24,10 @@ const rng = seededRandom(20260830)
 const MY_ADDRESS = 'bitcoincash:qqlrzp23w08434twmvr4fxw672whkjy0py26r63g3d'
 const CHARS = 'qpzry9x8gf2tvdw0s3jn54khce6mua7l'
 
+function broadcastHex (wallet, index = 0) {
+  return Buffer.from(wallet.broadcasts[index].msg).toString('hex')
+}
+
 // Deterministic 20-byte hash160 hex for any input string, mirroring what a
 // real wallet's bch-js produces for a valid cash address.
 function hash20 (s) {
@@ -86,9 +90,9 @@ test('mute broadcasts exactly one hash160 payload with the mute prefix', async (
 
       return wallet.broadcasts.length === 1 &&
         wallet.broadcasts[0].prefix === MemoMute.MEMO_MUTE_PREFIX &&
-        Buffer.isBuffer(wallet.broadcasts[0].msg) &&
+        wallet.broadcasts[0].msg instanceof Uint8Array &&
         wallet.broadcasts[0].msg.length === MemoMute.PK_HASH_LENGTH &&
-        wallet.broadcasts[0].msg.toString('hex') === hash20(addr)
+        broadcastHex(wallet, 0) === hash20(addr)
     },
     { label: 'mute broadcast conservation and hash160 length' }
   )
@@ -104,9 +108,9 @@ test('unmute broadcasts exactly one hash160 payload with the unmute prefix', asy
 
       return wallet.broadcasts.length === 1 &&
         wallet.broadcasts[0].prefix === MemoMute.MEMO_UNMUTE_PREFIX &&
-        Buffer.isBuffer(wallet.broadcasts[0].msg) &&
+        wallet.broadcasts[0].msg instanceof Uint8Array &&
         wallet.broadcasts[0].msg.length === MemoMute.PK_HASH_LENGTH &&
-        wallet.broadcasts[0].msg.toString('hex') === hash20(addr)
+        broadcastHex(wallet, 0) === hash20(addr)
     },
     { label: 'unmute broadcast conservation and hash160 length' }
   )
diff --git a/psf-memo-client/test/unit/memo-follow.test.js b/psf-memo-client/test/unit/memo-follow.test.js
index 216b07c..4c73272 100644
--- a/psf-memo-client/test/unit/memo-follow.test.js
+++ b/psf-memo-client/test/unit/memo-follow.test.js
@@ -17,6 +17,10 @@ const MY_ADDRESS = 'bitcoincash:qqlrzp23w08434twmvr4fxw672whkjy0py26r63g3d'
 const FOLLOWEE_ADDRESS = 'bitcoincash:qr95sy3j9xwd2ap32xkykttr4cvcu7as4y0qverfuy'
 const FOLLOWEE_HASH160 = 'cb481232299cd5743151ac4b2d63ae198e7bb0a9'
 
+function broadcastHex (wallet, index = 0) {
+  return Buffer.from(wallet.broadcasts[index].msg).toString('hex')
+}
+
 function makeBchjs () {
   return {
     Address: {
@@ -63,8 +67,8 @@ test('follow broadcasts with the Memo follow prefix and hash160 payload', async
 
   assert.equal(wallet.broadcasts.length, 1)
   assert.equal(wallet.broadcasts[0].prefix, MemoFollow.MEMO_FOLLOW_PREFIX)
-  assert.ok(Buffer.isBuffer(wallet.broadcasts[0].msg))
-  assert.equal(wallet.broadcasts[0].msg.toString('hex'), FOLLOWEE_HASH160)
+  assert.equal(wallet.broadcasts[0].msg.length, MemoFollow.PK_HASH_LENGTH)
+  assert.equal(broadcastHex(wallet, 0), FOLLOWEE_HASH160)
 })
 
 test('unfollow broadcasts with the Memo unfollow prefix and hash160 payload', async () => {
@@ -75,7 +79,8 @@ test('unfollow broadcasts with the Memo unfollow prefix and hash160 payload', as
 
   assert.equal(wallet.broadcasts.length, 1)
   assert.equal(wallet.broadcasts[0].prefix, MemoFollow.MEMO_UNFOLLOW_PREFIX)
-  assert.equal(wallet.broadcasts[0].msg.toString('hex'), FOLLOWEE_HASH160)
+  assert.equal(wallet.broadcasts[0].msg.length, MemoFollow.PK_HASH_LENGTH)
+  assert.equal(broadcastHex(wallet, 0), FOLLOWEE_HASH160)
 })
 
 test('follow reflects the new follow state on the profile store', async () => {
diff --git a/psf-memo-client/test/unit/memo-mute.test.js b/psf-memo-client/test/unit/memo-mute.test.js
index 896f70e..7553724 100644
--- a/psf-memo-client/test/unit/memo-mute.test.js
+++ b/psf-memo-client/test/unit/memo-mute.test.js
@@ -12,6 +12,10 @@ const MY_ADDRESS = 'bitcoincash:qqlrzp23w08434twmvr4fxw672whkjy0py26r63g3d'
 const MUTEE_ADDRESS = 'bitcoincash:qr95sy3j9xwd2ap32xkykttr4cvcu7as4y0qverfuy'
 const MUTEE_HASH160 = 'cb481232299cd5743151ac4b2d63ae198e7bb0a9'
 
+function broadcastHex (wallet, index = 0) {
+  return Buffer.from(wallet.broadcasts[index].msg).toString('hex')
+}
+
 function makeBchjs () {
   return {
     Address: {
@@ -58,8 +62,8 @@ test('mute broadcasts with the Memo mute prefix and hash160 payload', async () =
 
   assert.equal(wallet.broadcasts.length, 1)
   assert.equal(wallet.broadcasts[0].prefix, MemoMute.MEMO_MUTE_PREFIX)
-  assert.ok(Buffer.isBuffer(wallet.broadcasts[0].msg))
-  assert.equal(wallet.broadcasts[0].msg.toString('hex'), MUTEE_HASH160)
+  assert.equal(wallet.broadcasts[0].msg.length, MemoMute.PK_HASH_LENGTH)
+  assert.equal(broadcastHex(wallet, 0), MUTEE_HASH160)
 })
 
 test('unmute broadcasts with the Memo unmute prefix and hash160 payload', async () => {
@@ -70,7 +74,8 @@ test('unmute broadcasts with the Memo unmute prefix and hash160 payload', async
 
   assert.equal(wallet.broadcasts.length, 1)
   assert.equal(wallet.broadcasts[0].prefix, MemoMute.MEMO_UNMUTE_PREFIX)
-  assert.equal(wallet.broadcasts[0].msg.toString('hex'), MUTEE_HASH160)
+  assert.equal(wallet.broadcasts[0].msg.length, MemoMute.PK_HASH_LENGTH)
+  assert.equal(broadcastHex(wallet, 0), MUTEE_HASH160)
 })
 
 test('mute reflects the new mute state on the profile store', async () => {