diff --git a/pkg/webui/console/views/device-general-settings/index.js b/pkg/webui/console/views/device-general-settings/index.js
index a34ed6d021..8e6c895c45 100644
--- a/pkg/webui/console/views/device-general-settings/index.js
+++ b/pkg/webui/console/views/device-general-settings/index.js
@@ -36,7 +36,6 @@ import {
   selectNsConfig,
 } from '@ttn-lw/lib/selectors/env'
 
-import { hexToBase64 } from '@console/lib/bytes'
 import {
   mayEditApplicationDeviceKeys,
   mayReadApplicationDeviceKeys,
@@ -101,9 +100,7 @@ const DeviceGeneralSettings = () => {
     const {
       ids: { dev_eui: devEui, join_eui: joinEui },
     } = device
-    await dispatch(
-      attachPromise(unclaimDevice(appId, devId, hexToBase64(devEui), hexToBase64(joinEui))),
-    )
+    await dispatch(attachPromise(unclaimDevice(appId, devId, devEui, joinEui)))
   }, [appId, devId, device, dispatch])
 
   const handleUnclaimFailure = useCallback(async () => {
diff --git a/sdk/js/src/service/claim.js b/sdk/js/src/service/claim.js
index 2340ac9cd6..b1894cdb3e 100644
--- a/sdk/js/src/service/claim.js
+++ b/sdk/js/src/service/claim.js
@@ -14,6 +14,7 @@
 
 import autoBind from 'auto-bind'
 
+import hexToBase64 from '../util/bytes'
 import Marshaler from '../util/marshaler'
 
 class DeviceClaim {
@@ -62,8 +63,8 @@ class DeviceClaim {
     }
 
     const response = await this._api.EndDeviceClaimingServer.Unclaim(params, {
-      dev_eui: devEui,
-      join_eui: joinEui,
+      dev_eui: hexToBase64(devEui),
+      join_eui: hexToBase64(joinEui),
     })
 
     return Marshaler.payloadSingleResponse(response)
diff --git a/sdk/js/src/util/bytes.js b/sdk/js/src/util/bytes.js
new file mode 100644
index 0000000000..411c485400
--- /dev/null
+++ b/sdk/js/src/util/bytes.js
@@ -0,0 +1,46 @@
+// Copyright © 2023 The Things Network Foundation, The Things Industries B.V.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/**
+ * Converts hex encoded string to base64.
+ *
+ * @param {string} str - Hex encoded string.
+ * @returns {string} - `str` base64 encoded.
+ */
+export const hexToBase64 = str =>
+  btoa(
+    String.fromCharCode.apply(
+      null,
+      str
+        .replace(/\r|\n/g, '')
+        .replace(/([\da-fA-F]{2}) ?/g, '0x$1 ')
+        .replace(/ +$/, '')
+        .split(' '),
+    ),
+  )
+
+/**
+ * Converts base64 encoded string to hex.
+ *
+ * @param {string} str - Base64 encoded string.
+ * @returns {string} - `str` hex encoded.
+ */
+export const base64ToHex = str =>
+  Array.from(atob(str.replace(/[ \r\n]+$/, '')))
+    .map(char => {
+      const tmp = char.charCodeAt(0).toString(16)
+
+      return tmp.length > 1 ? tmp : `0${tmp}`
+    })
+    .join('')