diff --git a/src/plugins/api/api.ts b/src/plugins/api/api.ts
index 0fbbf9c3055..20848054b21 100644
--- a/src/plugins/api/api.ts
+++ b/src/plugins/api/api.ts
@@ -136,6 +136,10 @@ export class Api {
     }
   }
 
+  /**
+   * Get a system savedata.
+   * @param sessionId The savedata session ID
+   */
   public async getSystemSavedata(sessionId: string) {
     try {
       const params = new URLSearchParams();
@@ -177,6 +181,26 @@ export class Api {
     return null;
   }
 
+  /**
+   * Update a system savedata.
+   * @param clientSessionId The savedata session ID
+   * @param rawSystemData The raw {@linkcode SystemSaveData}
+   * @returns an error message if something went wrong
+   */
+  public async updateSystemSavedata(clientSessionId: string, rawSystemData: string) {
+    try {
+      const params = new URLSearchParams();
+      params.append("clientSessionId", clientSessionId);
+      const response = await this.doPost<string>(`/savedata/system/update?${params}`, rawSystemData);
+
+      return (await response.json()) as string;
+    } catch (err) {
+      console.warn("Could not update system savedata!", err);
+    }
+
+    return null;
+  }
+
   /**
    * Get a session savedata.
    * @param slotId The slot ID to load
@@ -285,15 +309,19 @@ export class Api {
    * @param bodyData The body-data to send.
    * @param dataType The data-type of the {@linkcode bodyData}.
    */
-  private async doPost<D extends Record<string, any>>(path: string, bodyData: D, dataType: DataType = "json") {
+  private async doPost<D>(path: string, bodyData: D, dataType: DataType = "json") {
     let body: string = "";
     const headers: HeadersInit = {};
 
     if (dataType === "json") {
-      body = JSON.stringify(bodyData);
+      body = typeof bodyData === "string" ? bodyData : JSON.stringify(bodyData);
       headers["Content-Type"] = "application/json";
     } else if (dataType === "form-urlencoded") {
-      body = new URLSearchParams(Object.entries<any>(bodyData).map(([k, v]) => [k, v.toString()])).toString();
+      if (bodyData instanceof Object) {
+        body = new URLSearchParams(Object.entries<any>(bodyData).map(([k, v]) => [k, v.toString()])).toString();
+      } else {
+        console.warn("Could not add body data to form-urlencoded!", bodyData);
+      }
       headers["Content-Type"] = "application/x-www-form-urlencoded";
     } else {
       console.warn(`Unsupported data type: ${dataType}`);
diff --git a/src/system/game-data.ts b/src/system/game-data.ts
index e87da3cdeae..f3f32b7805b 100644
--- a/src/system/game-data.ts
+++ b/src/system/game-data.ts
@@ -398,8 +398,7 @@ export class GameData {
       localStorage.setItem(`data_${loggedInUser?.username}`, encrypt(systemData, bypassLogin));
 
       if (!bypassLogin) {
-        Utils.apiPost(`savedata/system/update?clientSessionId=${clientSessionId}`, systemData, undefined, true)
-          .then(response => response.text())
+        api.updateSystemSavedata(clientSessionId, systemData)
           .then(error => {
             this.scene.ui.savingIcon.hide();
             if (error) {