diff --git a/nx/include/switch/services/set.h b/nx/include/switch/services/set.h
index 8516180f..2b40738e 100644
--- a/nx/include/switch/services/set.h
+++ b/nx/include/switch/services/set.h
@@ -35,6 +35,14 @@ typedef enum
     SetLanguage_Total,      ///< Total languages supported by this enum.
 } SetLanguage;
 
+/// Region codes.
+typedef enum {
+    SetRegion_JPN = 0, ///< Japan
+    SetRegion_USA = 1, ///< The Americas
+    SetRegion_EUR = 2, ///< Europe
+    SetRegion_AUS = 3, ///< Australia/New Zealand
+} SetRegion;
+
 /// Command IDs for setsysGetFlag/setsysSetFlag.
 typedef enum {
     SetSysFlag_LockScreen = 7,
@@ -81,13 +89,16 @@ Result setGetAvailableLanguageCodes(s32 *total_entries, u64 *LanguageCodes, size
 Result setGetAvailableLanguageCodeCount(s32 *total);
 
 /// Gets the RegionCode.
-Result setGetRegionCode(s32 *RegionCode);
+Result setGetRegionCode(SetRegion *out);
 
 Result setsysInitialize(void);
 void setsysExit(void);
 
 /// Gets the current system theme.
-Result setsysGetColorSetId(ColorSetId* out);
+Result setsysGetColorSetId(ColorSetId *out);
+
+/// Sets the current system theme.
+Result setsysSetColorSetId(ColorSetId id);
 
 /**
  * @brief Gets the size of a settings item value.
diff --git a/nx/source/services/set.c b/nx/source/services/set.c
index 9e5f23da..1ff7296a 100644
--- a/nx/source/services/set.c
+++ b/nx/source/services/set.c
@@ -279,7 +279,7 @@ Result setGetAvailableLanguageCodeCount(s32 *total) {
     return rc;
 }
 
-Result setGetRegionCode(s32 *RegionCode) {
+Result setGetRegionCode(SetRegion *out) {
     IpcCommand c;
     ipcInitialize(&c);
 
@@ -307,13 +307,13 @@ Result setGetRegionCode(s32 *RegionCode) {
 
         rc = resp->result;
 
-        if (R_SUCCEEDED(rc) && RegionCode) *RegionCode = resp->RegionCode;
+        if (R_SUCCEEDED(rc) && out) *out = resp->RegionCode;
     }
 
     return rc;
 }
 
-Result setsysGetColorSetId(ColorSetId* out)
+Result setsysGetColorSetId(ColorSetId *out)
 {
     IpcCommand c;
     ipcInitialize(&c);
@@ -345,7 +345,40 @@ Result setsysGetColorSetId(ColorSetId* out)
     }
 
     return rc;
+}
 
+Result setsysSetColorSetId(ColorSetId id)
+{
+    IpcCommand c;
+    ipcInitialize(&c);
+
+    struct {
+        u64 magic;
+        u64 cmd_id;
+        s32 id;
+    } *raw;
+
+    raw = ipcPrepareHeader(&c, sizeof(*raw));
+
+    raw->magic = SFCI_MAGIC;
+    raw->cmd_id = 24;
+    raw->id = id;
+
+    Result rc = serviceIpcDispatch(&g_setsysSrv);
+
+    if (R_SUCCEEDED(rc)) {
+        IpcParsedCommand r;
+        ipcParse(&r);
+
+        struct {
+            u64 magic;
+            u64 result;
+        } *resp = r.Raw;
+
+        rc = resp->result;
+    }
+
+    return rc;
 }
 
 Result setsysGetSettingsItemValue(const char *name, const char *item_key, void *value_out, size_t value_out_size) {