diff --git a/Core/MMC3_52.h b/Core/MMC3_52.h
index 2878225b..26f327b8 100644
--- a/Core/MMC3_52.h
+++ b/Core/MMC3_52.h
@@ -27,11 +27,12 @@ protected:
 	{
 		if(_extraReg & 0x40) {
 			page &= 0x7F;
-			page |= ((_extraReg & 0x04) | ((_extraReg >> 4) & 0x03)) << 7;
+			page |= (((_extraReg & 0x20) >> 3) | ((_extraReg & 0x10) >> 4) | ((_extraReg & 0x04) >> 1)) << 7;
 		} else {
 			page &= 0xFF;
-			page |= ((_extraReg & 0x04) | ((_extraReg >> 4) & 0x02)) << 7;
+			page |= (((_extraReg & 0x20) >> 3) | ((_extraReg & 0x10) >> 4)) << 7;
 		}
+
 		MMC3::SelectCHRPage(slot, page, memoryType);
 	}
 
@@ -62,4 +63,4 @@ protected:
 			MMC3::WriteRegister(addr, value);
 		}
 	}
-};
\ No newline at end of file
+};