--- xnu/xnu-201.19.3/iokit/Kernel/IONVRAM.cpp
+++ xnu/xnu-124.13/iokit/Kernel/IONVRAM.cpp
@@ -280,7 +280,8 @@
 IOReturn IODTNVRAM::readXPRAM(IOByteCount offset, UInt8 *buffer,
 			      IOByteCount length)
 {
-  if (_xpramImage == 0) return kIOReturnUnsupported;
+  if ((_nvramImage == 0) || (_xpramPartitionOffset == 0))
+    return kIOReturnNotReady;
   
   if ((buffer == 0) || (length <= 0) || (offset < 0) ||
       (offset + length > kIODTNVRAMXPRAMSize))
@@ -294,7 +295,8 @@
 IOReturn IODTNVRAM::writeXPRAM(IOByteCount offset, UInt8 *buffer,
 			       IOByteCount length)
 {
-  if (_xpramImage == 0) return kIOReturnUnsupported;
+  if ((_nvramImage == 0) || (_xpramPartitionOffset == 0))
+    return kIOReturnNotReady;
   
   if ((buffer == 0) || (length <= 0) || (offset < 0) ||
       (offset + length > kIODTNVRAMXPRAMSize))