diff --git a/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.cpp b/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.cpp
index 189b15655..2f618b122 100644
--- a/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.cpp
+++ b/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.cpp
@@ -223,28 +223,23 @@ NvResult nvhost_ctrl_gpu::ZCullGetInfo(IoctlNvgpuGpuZcullGetInfoArgs& params) {
 }
 
 NvResult nvhost_ctrl_gpu::ZBCSetTable(IoctlZbcSetTable& params) {
-    LOG_DEBUG(Service_NVDRV, "called with index={}, format={}, mode={}",
+    LOG_DEBUG(Service_NVDRV, "called. index={}, format={}, mode={}",
               params.color_ds_table_index, params.format, params.mode);
 
-    // Validate parameters
     if (params.color_ds_table_index >= MaxZBCTableSize || params.format >= MaxZBCFormats) {
-        return NvResult::InvalidArgument;
+        return NvResult::BadParameter;
     }
 
-    // Store the color/depth values
     switch (params.mode) {
-    case ZBCTableMode::COLOR:
-        // Store color values
-        std::memcpy(zbc_color_table[params.color_ds_table_index].color_ds,
-                    params.color_ds, sizeof(params.color_ds));
+    case 0:  // Color table
+        std::memcpy(&zbc_color_table[params.color_ds_table_index].color_ds,
+                   &params.color_ds, sizeof(params.color_ds));
         break;
-    case ZBCTableMode::DEPTH:
-        // Store depth values
-        std::memcpy(zbc_depth_table[params.color_ds_table_index].depth,
-                    params.depth, sizeof(params.depth));
+    case 1:  // Depth table
+        zbc_depth_table[params.color_ds_table_index].depth[0] = params.depth;
         break;
     default:
-        return NvResult::InvalidArgument;
+        return NvResult::BadParameter;
     }
 
     return NvResult::Success;
diff --git a/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.h b/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.h
index 2009de8c5..2ad752c07 100644
--- a/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.h
+++ b/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.h
@@ -45,11 +45,11 @@ private:
 
     struct ZBCColorEntry {
         u32 color_ds[4];
-    };
+    } __attribute__((packed));
 
     struct ZBCDepthEntry {
         u32 depth[4];
-    };
+    } __attribute__((packed));
 
     std::array<ZBCColorEntry, MaxZBCTableSize> zbc_color_table{};
     std::array<ZBCDepthEntry, MaxZBCTableSize> zbc_depth_table{};
@@ -139,14 +139,18 @@ private:
     static_assert(sizeof(IoctlNvgpuGpuZcullGetInfoArgs) == 40,
                   "IoctlNvgpuGpuZcullGetInfoArgs is incorrect size");
 
+#pragma pack(push, 1)
     struct IoctlZbcSetTable {
-        u32_le color_ds[4];
-        u32_le color_l2[4];
-        u32_le depth;
-        u32_le format;
-        u32_le type;
-    };
-    static_assert(sizeof(IoctlZbcSetTable) == 44, "IoctlZbcSetTable is incorrect size");
+        u32 color_ds_table_index;
+        u32 format;
+        u32 mode;
+        u32 color_ds[4];  // 16 bytes
+        u32 color_l2[4];  // 16 bytes
+        u32 depth;        // 4 bytes
+    } __attribute__((packed));  // Use GCC's packed attribute
+#pragma pack(pop)
+
+    static_assert(sizeof(IoctlZbcSetTable) == 48, "IoctlZbcSetTable is incorrect size");
 
     struct IoctlZbcQueryTable {
         u32_le color_ds[4];