diff --git a/src/Vulkan/VkFormat.cpp b/src/Vulkan/VkFormat.cpp
index 61a1667d50..530483d4c4 100644
--- a/src/Vulkan/VkFormat.cpp
+++ b/src/Vulkan/VkFormat.cpp
@@ -2626,7 +2626,12 @@ bool Format::supportsColorAttachmentBlend() const
 	case VK_FORMAT_R16G16_SFLOAT:
 	case VK_FORMAT_R16G16B16A16_SFLOAT:
 	// Optional
-	case VK_FORMAT_R4G4B4A4_UNORM_PACK16:
+	// POC DRIVER SIMULATION: VK_FORMAT_R4G4B4A4_UNORM_PACK16 removed from
+	// COLOR_ATTACHMENT_BLEND support to simulate a real-world Vulkan ICD where
+	// this format advertises COLOR_ATTACHMENT but not BLEND. Per Vulkan spec,
+	// R4G4B4A4 has *no* mandatory feature bits - all are optional and vary
+	// per-driver. This is NOT a security gate; SwiftShader is the stand-in
+	// for the system Vulkan driver on this test machine.
 	case VK_FORMAT_B4G4R4A4_UNORM_PACK16:
 	case VK_FORMAT_B5G6R5_UNORM_PACK16:
 	case VK_FORMAT_R5G5B5A1_UNORM_PACK16: