diff --git a/native/account/registration/avatar-selection.react.js b/native/account/registration/avatar-selection.react.js
--- a/native/account/registration/avatar-selection.react.js
+++ b/native/account/registration/avatar-selection.react.js
@@ -36,8 +36,8 @@
 
 export type AvatarSelectionParams = {
   +userSelections: {
-    +coolOrNerdMode?: CoolOrNerdMode,
-    +keyserverURL?: string,
+    +coolOrNerdMode?: ?CoolOrNerdMode,
+    +keyserverURL?: ?string,
     +accountSelection: AccountSelection,
     +farcasterID: ?string,
   },
diff --git a/native/account/registration/connect-ethereum.react.js b/native/account/registration/connect-ethereum.react.js
--- a/native/account/registration/connect-ethereum.react.js
+++ b/native/account/registration/connect-ethereum.react.js
@@ -44,8 +44,8 @@
 
 export type ConnectEthereumParams = {
   +userSelections: {
-    +coolOrNerdMode?: CoolOrNerdMode,
-    +keyserverURL?: string,
+    +coolOrNerdMode?: ?CoolOrNerdMode,
+    +keyserverURL?: ?string,
     +farcasterID: ?string,
   },
 };
diff --git a/native/account/registration/password-selection.react.js b/native/account/registration/password-selection.react.js
--- a/native/account/registration/password-selection.react.js
+++ b/native/account/registration/password-selection.react.js
@@ -23,8 +23,8 @@
 
 export type PasswordSelectionParams = {
   +userSelections: {
-    +coolOrNerdMode?: CoolOrNerdMode,
-    +keyserverURL?: string,
+    +coolOrNerdMode?: ?CoolOrNerdMode,
+    +keyserverURL?: ?string,
     +farcasterID: ?string,
     +username: string,
   },
diff --git a/native/account/registration/registration-terms.react.js b/native/account/registration/registration-terms.react.js
--- a/native/account/registration/registration-terms.react.js
+++ b/native/account/registration/registration-terms.react.js
@@ -33,8 +33,8 @@
 
 export type RegistrationTermsParams = {
   +userSelections: {
-    +coolOrNerdMode?: CoolOrNerdMode,
-    +keyserverURL?: string,
+    +coolOrNerdMode?: ?CoolOrNerdMode,
+    +keyserverURL?: ?string,
     +farcasterID: ?string,
     +accountSelection: AccountSelection,
     +avatarData: ?AvatarData,
diff --git a/native/account/registration/registration-types.js b/native/account/registration/registration-types.js
--- a/native/account/registration/registration-types.js
+++ b/native/account/registration/registration-types.js
@@ -38,8 +38,8 @@
     };
 
 export type RegistrationServerCallInput = {
-  +coolOrNerdMode?: CoolOrNerdMode,
-  +keyserverURL?: string,
+  +coolOrNerdMode?: ?CoolOrNerdMode,
+  +keyserverURL?: ?string,
   +farcasterID: ?string,
   +accountSelection: AccountSelection,
   +avatarData: ?AvatarData,
diff --git a/native/account/registration/siwe-backup-message-creation.react.js b/native/account/registration/siwe-backup-message-creation.react.js
--- a/native/account/registration/siwe-backup-message-creation.react.js
+++ b/native/account/registration/siwe-backup-message-creation.react.js
@@ -140,8 +140,8 @@
 
 export type CreateSIWEBackupMessageParams = {
   +userSelections: {
-    +coolOrNerdMode?: CoolOrNerdMode,
-    +keyserverURL?: string,
+    +coolOrNerdMode?: ?CoolOrNerdMode,
+    +keyserverURL?: ?string,
     +farcasterID: ?string,
     +accountSelection: AccountSelection,
     +avatarData: ?AvatarData,
diff --git a/native/account/registration/username-selection.react.js b/native/account/registration/username-selection.react.js
--- a/native/account/registration/username-selection.react.js
+++ b/native/account/registration/username-selection.react.js
@@ -37,8 +37,8 @@
 
 export type UsernameSelectionParams = {
   +userSelections: {
-    +coolOrNerdMode?: CoolOrNerdMode,
-    +keyserverURL?: string,
+    +coolOrNerdMode?: ?CoolOrNerdMode,
+    +keyserverURL?: ?string,
     +farcasterID: ?string,
   },
 };
@@ -73,12 +73,12 @@
 
   const { userSelections } = props.route.params;
   const { keyserverURL } = userSelections;
-  const serverCallParamOverride = React.useMemo(
-    () => ({
-      urlPrefix: keyserverURL,
-    }),
-    [keyserverURL],
-  );
+  const serverCallParamOverride = React.useMemo(() => {
+    if (keyserverURL) {
+      return { urlPrefix: keyserverURL };
+    }
+    return undefined;
+  }, [keyserverURL]);
 
   const exactSearchUserCall = useLegacyAshoatKeyserverCall(
     exactSearchUser,