diff --git a/Editor/Resources/Builder/BuilderWindow.cs b/Editor/Resources/Builder/BuilderWindow.cs
index c5e8c1a8..b00e0cb6 100644
--- a/Editor/Resources/Builder/BuilderWindow.cs
+++ b/Editor/Resources/Builder/BuilderWindow.cs
@@ -1195,7 +1195,8 @@ public IEnumerator Json<T>(string url, Action<T> callback)
         yield return uwr.SendWebRequest();
         if (uwr.result != UnityWebRequest.Result.Success)
         {
-            throw new System.Exception(uwr.error);
+            string errorMsg = $"HTTP/{uwr.responseCode}: {uwr.error}";
+            throw new System.Exception(errorMsg);
         }
         else
         {
@@ -1218,7 +1219,8 @@ public IEnumerator Json<T>(string url, T postData, Action<string> callback, Dict
         if (uwr.result != UnityWebRequest.Result.Success)
         {
             Debug.LogError(url + ":" + JsonUtility.ToJson(postData));
-            throw new System.Exception(uwr.error);
+            string errorMsg = $"HTTP/{uwr.responseCode}: {uwr.error}";
+            throw new System.Exception(errorMsg);
         }
         else
         {
@@ -1323,15 +1325,28 @@ private IEnumerator UploadAvatar(Action callback)
                 {
                     status.AddStatus("Posted avatar successfully.");
                     Debug.Log("Posted avatar successfully.");
-                    callback();
                     selectedExistingAvatar = av;
                     SetupExistingAvatars();
                     EditorCoroutineUtility.StartCoroutine(sq.AttachAvatar((slot) =>
                     {
                         status.AddStatus("Avatar attached successfully.");
-                        Debug.Log("Avatar attached successfully.");
-                        callback();
-                        EditorCoroutineUtility.StartCoroutine(sq.SelectAvatar(() => { }, Debug.LogException, slot.UserAvatarId), this);
+                        Debug.Log("Avatar attached successfully.");                        
+						if (slot == null)
+                        {
+                            status.AddStatus("Failed to select avatar: attach response was empty.");
+                            Debug.LogError("Failed to select avatar: attach response was empty.");
+                            callback();
+                            return;
+                        }
+                        EditorCoroutineUtility.StartCoroutine(sq.SelectAvatar(() =>
+                        {
+                            callback();
+                        }, e =>
+                        {
+                            status.AddStatus("Failed to select avatar: " + e);
+                            Debug.LogError("Failed to select avatar: " + e);
+                            callback();
+                        }, slot.UserAvatarId), this);
                     }, e =>
                     {
                         status.AddStatus("Failed to attach avatar: " + e);
diff --git a/Editor/Resources/Builder/SideQuest/SqEditorAppApi.cs b/Editor/Resources/Builder/SideQuest/SqEditorAppApi.cs
index 9d0719c3..c1002252 100644
--- a/Editor/Resources/Builder/SideQuest/SqEditorAppApi.cs
+++ b/Editor/Resources/Builder/SideQuest/SqEditorAppApi.cs
@@ -1,4 +1,4 @@
-using Newtonsoft.Json;
+using Newtonsoft.Json;
 using System;
 using System.Collections;
 using System.Collections.Generic;
@@ -95,7 +95,7 @@ public IEnumerator UpdateAvatar(Action<SqEditorAvatar> OnCompleted, Action<Excep
             yield return JsonPost<SqEditorAvatar>($"/v2/avatars/{avatarId}", new SqEditorAvatar() { HighId = highId, LowId = lowId, PreviewImage = screenshotId, Public = ispublic, Version = 2, Name = name}, (av) =>
             {
                 OnCompleted?.Invoke(av);
-            }, OnError, true, false, "PATCH");
+            }, OnError, true, false, "PUT");
         }
         public IEnumerator GetAvatars(Action<List<SqEditorAvatar>> OnCompleted, Action<Exception> OnError)
         {
@@ -126,7 +126,7 @@ public IEnumerator SelectAvatar(Action OnCompleted, Action<Exception> OnError, l
             yield return JsonPost<SqAvatarSlot>($"/v2/users/me/avatars/{userAvatarId}", new SqAvatarSlotSelect() { IsSelected = true}, (u) =>
             {
                 OnCompleted?.Invoke();
-            }, OnError, true, false,"PATCH");
+            }, OnError, true, false);
         }
         /// <summary>
         /// Get a list of the currently logged in sidequest user's achievements
@@ -533,6 +533,7 @@ private async Task<long> UploadFileWithRetryAsync(string url, byte[] data, strin
                     using (var request = new HttpRequestMessage(HttpMethod.Put, url))
                     {
                         request.Content = content;
+                        content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue(GetMimeType(name));
 
                         // Set timeout for this specific request
                         using (var cts = new CancellationTokenSource(TimeSpan.FromMinutes(5)))
@@ -891,6 +892,26 @@ private void LoadData()
             }
         }
 
+        private string GetMimeType(string fileName)
+        {
+            var ext = Path.GetExtension(fileName)?.ToLower();
+            switch (ext)
+            {
+				case ".html": return "text/html";
+				case ".js": return "application/javascript";
+                case ".glb": return "model/gltf-binary";
+                case ".gltf": return "model/gltf+json";
+                case ".png": return "image/png";
+                case ".jpg":
+                case ".jpeg": return "image/jpeg";
+                case ".gif": return "image/gif";
+                case ".zip": return "application/zip";
+                case ".json": return "application/json";
+                case ".txt": return "text/plain";
+                default: return "application/octet-stream";
+            }
+        }
+
         private void SaveData()
         {
             File.WriteAllText(Config.DataFile, JsonConvert.SerializeObject(Data));
diff --git a/Editor/Resources/Builder/SideQuest/SqEditorModels.cs b/Editor/Resources/Builder/SideQuest/SqEditorModels.cs
index 84b8944e..49f01037 100644
--- a/Editor/Resources/Builder/SideQuest/SqEditorModels.cs
+++ b/Editor/Resources/Builder/SideQuest/SqEditorModels.cs
@@ -1,4 +1,4 @@
-using Newtonsoft.Json;
+using Newtonsoft.Json;
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -492,6 +492,9 @@ public class SqAvatarSlot
         
         [JsonProperty("is_selected")]
         public bool IsSelected { get; set; }
+
+        [JsonProperty("is_public", NullValueHandling = NullValueHandling.Ignore)]
+        public bool? IsPublic { get; set; }
     }
     
     public class SqAvatarSlotSelect