diff --git a/jtag/data/atmel/atmega128/atmega128 b/jtag/data/atmel/atmega128/atmega128
index 04730902..4527d34e 100644
--- a/jtag/data/atmel/atmega128/atmega128
+++ b/jtag/data/atmel/atmega128/atmega128
@@ -26,27 +26,34 @@
 #     128K Bytes In-System Programmable Flash", 2002, Rev. 2467E-AVR-05/02
 #
 
+# mandatory data registers
+register	BSR	205	# see Table 106 in [1]
+register	BR	1
+# optional data registers
+register	DIR	32
+# user-defined registers
+register	RR	1	# Reset Register
+register	PER	16	# Programming Enable Register
+register	PCR	15	# Programming Command Register
+register	VFPLR	2048	# Virtual Flash Page Load Register
+register	VFPRR	2056	# Virtual Flash Page Read Register
+
 # see page 250 in [1]
 instruction length 4
-
 # mandatory instructions
-instruction EXTEST		0000	# see page 250 in [1]
-instruction SAMPLE/PRELOAD	0010	# see page 251 in [1]
-instruction BYPASS		1111	# see page 251 in [1]
-
+instruction EXTEST		0000	BSR	# see page 250 in [1]
+instruction SAMPLE/PRELOAD	0010	BSR	# see page 251 in [1]
+instruction BYPASS		1111	BR	# see page 251 in [1]
 # optional instructions
-instruction IDCODE		0001	# see page 250 in [1]
-
+instruction IDCODE		0001	DIR	# see page 250 in [1]
 # user-defined instructions
-instruction AVR_RESET		1100	# see page 251 and page 303 in [1]
-instruction PRIVATE0		1000	# see page 246 in [1]
-instruction PRIVATE1		1001	# see page 246 in [1]
-instruction PRIVATE2		1010	# see page 246 in [1]
-instruction PRIVATE3		1011	# see page 246 in [1]
-instruction PROG_ENABLE		0100	# see page 303 in [1]
-instruction PROG_COMMANDS	0101	# see page 304 in [1]
-instruction PROG_PAGELOAD	0110	# see page 304 in [1]
-instruction PROG_PAGEREAD	0111	# see page 304 in [1]
-
-# see Table 106 in [1]
-boundary length 205
+instruction AVR_RESET		1100	RR	# see page 251 and page 303 in [1]
+# unknown data registers fo PRIVATE? instructions
+#instruction PRIVATE0		1000	# see page 246 in [1]
+#instruction PRIVATE1		1001	# see page 246 in [1]
+#instruction PRIVATE2		1010	# see page 246 in [1]
+#instruction PRIVATE3		1011	# see page 246 in [1]
+instruction PROG_ENABLE		0100	PER	# see page 303 in [1]
+instruction PROG_COMMANDS	0101	PCR	# see page 304 in [1]
+instruction PROG_PAGELOAD	0110	VFPLR	# see page 304 in [1]
+instruction PROG_PAGEREAD	0111	VFPRR	# see page 304 in [1]