diff --git a/CONFIG.md b/CONFIG.md
index 7b75bcd1..3df98c2d 100644
--- a/CONFIG.md
+++ b/CONFIG.md
@@ -103,6 +103,10 @@ Adds support for the IEEC bus - for serial printers, disk drives, etc.
 
 Needs over 1000 bytes in KERNAL segment. If unsure - enable.
 
+### `CONFIG_IEC_BLANK_SCREEN`
+
+Causes screen blanking during some IEC operations (currently only JiffyDOS file loading) to increase the data transfer performance.
+
 ### `CONFIG_IEC_JIFFYDOS`
 
 Adds support for JiffyDOS fast protocol to the IEC bus.
diff --git a/bin/basic_generic.rom b/bin/basic_generic.rom
index ebdb04d8..b05583c6 100644
Binary files a/bin/basic_generic.rom and b/bin/basic_generic.rom differ
diff --git a/bin/basic_mega65.rom b/bin/basic_mega65.rom
index fdf8a5e2..402d2cb2 100644
Binary files a/bin/basic_mega65.rom and b/bin/basic_mega65.rom differ
diff --git a/bin/basic_testing.rom b/bin/basic_testing.rom
index fee95438..9159e416 100644
Binary files a/bin/basic_testing.rom and b/bin/basic_testing.rom differ
diff --git a/bin/basic_ultimate64.rom b/bin/basic_ultimate64.rom
index 6f12ef0a..dfcaafab 100644
Binary files a/bin/basic_ultimate64.rom and b/bin/basic_ultimate64.rom differ
diff --git a/bin/kernal_generic.rom b/bin/kernal_generic.rom
index c5e7be09..16b3cd5e 100644
Binary files a/bin/kernal_generic.rom and b/bin/kernal_generic.rom differ
diff --git a/bin/kernal_mega65.rom b/bin/kernal_mega65.rom
index 429d1c1c..73884db8 100644
Binary files a/bin/kernal_mega65.rom and b/bin/kernal_mega65.rom differ
diff --git a/bin/kernal_testing.rom b/bin/kernal_testing.rom
index 316e8159..a83f643a 100644
Binary files a/bin/kernal_testing.rom and b/bin/kernal_testing.rom differ
diff --git a/bin/kernal_ultimate64.rom b/bin/kernal_ultimate64.rom
index 97670f04..5792dd5e 100644
Binary files a/bin/kernal_ultimate64.rom and b/bin/kernal_ultimate64.rom differ
diff --git a/c64/,,config_generic.s b/c64/,,config_generic.s
index 25bca317..cba2e0d3 100644
--- a/c64/,,config_generic.s
+++ b/c64/,,config_generic.s
@@ -41,6 +41,7 @@
 // I/O devices
 
 #define CONFIG_IEC
+#define CONFIG_IEC_BLANK_SCREEN
 #define CONFIG_IEC_JIFFYDOS
 // #define CONFIG_TAPE_NORMAL     // please keep disabled for now
 #define CONFIG_TAPE_TURBO
diff --git a/c64/,,config_mega65.s b/c64/,,config_mega65.s
index 80f96095..2af64048 100644
--- a/c64/,,config_mega65.s
+++ b/c64/,,config_mega65.s
@@ -43,6 +43,7 @@
 // I/O devices
 
 #define CONFIG_IEC
+#define CONFIG_IEC_BLANK_SCREEN
 #define CONFIG_IEC_JIFFYDOS
 // #define CONFIG_TAPE_NORMAL     // please keep disabled for now
 // #define CONFIG_TAPE_TURBO
diff --git a/c64/,,config_testing.s b/c64/,,config_testing.s
index 652a3e5d..19376b5a 100644
--- a/c64/,,config_testing.s
+++ b/c64/,,config_testing.s
@@ -42,6 +42,7 @@
 // I/O devices
 
 #define CONFIG_IEC
+// #define CONFIG_IEC_BLANK_SCREEN
 #define CONFIG_IEC_JIFFYDOS
 // #define CONFIG_TAPE_NORMAL     // please keep disabled for now
 #define CONFIG_TAPE_TURBO
diff --git a/c64/,,config_ultimate64.s b/c64/,,config_ultimate64.s
index 7af94966..ea56cd38 100644
--- a/c64/,,config_ultimate64.s
+++ b/c64/,,config_ultimate64.s
@@ -41,6 +41,7 @@
 // I/O devices
 
 #define CONFIG_IEC
+#define CONFIG_IEC_BLANK_SCREEN
 #define CONFIG_IEC_JIFFYDOS
 // #define CONFIG_TAPE_NORMAL     // please keep disabled for now
 #define CONFIG_TAPE_TURBO
diff --git a/c64/kernal/iec/iec_wait1ms.s b/c64/kernal/iec/iec_wait1ms.s
index 464619c4..9e550f35 100644
--- a/c64/kernal/iec/iec_wait1ms.s
+++ b/c64/kernal/iec/iec_wait1ms.s
@@ -29,6 +29,8 @@ wait_x_bars: // additional entry point for tape support
 	dex
 	bne !-
 
+iec_wait_rts: // dummy RTS, for very short waits
+
 	rts
 
 
diff --git a/c64/kernal/iec_fast/load_jiffydos.s b/c64/kernal/iec_fast/load_jiffydos.s
index 51bf3bf3..126187c4 100644
--- a/c64/kernal/iec_fast/load_jiffydos.s
+++ b/c64/kernal/iec_fast/load_jiffydos.s
@@ -3,8 +3,6 @@
 // JiffyDOS protocol support for IEC - optimized load loop
 //
 
-// XXX option does not work yet
-// #define CONFIG_IEC_BLANK_SCREEN
 
 #if CONFIG_IEC_JIFFYDOS && !CONFIG_MEMORY_MODEL_60K
 
@@ -61,6 +59,10 @@ load_jiffydos_loop:
 
 #if CONFIG_IEC_BLANK_SCREEN
 
+	// It JiffyDOS needs some time here; waste few cycles
+	nop
+	jsr iec_wait_rts
+
 	// Ask device to start sending bits
 	sta CIA2_PRA
 
@@ -87,8 +89,8 @@ load_jiffydos_loop:
 	lsr
 	lsr
 
-	// Wait for the drive - we have time to increment offset, cycles: 2
-	iny
+	// Delay, JiffyDOS needs some time, 2 cycles
+	nop
 
 	// Get bits, cycles: 4 + 2 + 2 = 8
 	ora CIA2_PRA                       // bits 2 and 3 on CLK/DATA
@@ -105,7 +107,8 @@ load_jiffydos_loop:
 	eor C3PO
 	eor CIA2_PRA                       // bits 6 and 7 on CLK/DATA
 
-	// Store retrieved byte, cycles: 6 
+	// Store retrieved byte, cycles: 2 + 6 = 8 
+	iny                                // NTSC needs this delay
 	sta (EAL),y                        // not compatible with CONFIG_MEMORY_MODEL_60K
 
 	// Retrieve status bits, cycles: 4