diff --git a/rp06.cpp b/rp06.cpp
index a9ccb12..1005e4b 100644
--- a/rp06.cpp
+++ b/rp06.cpp
@@ -17,8 +17,9 @@
 constexpr const unsigned NSECT       = 22;               // sectors per track
 constexpr const unsigned NTRAC       = 19;               // tracks per cylinder
 constexpr const unsigned SECTOR_SIZE = 512;
+constexpr const uint16_t default_DS  = 0400 /* drive present */ | 010000 /* medium on-line */ | 0100 /* volume valid */ | 0200 /* drive ready */;
 
-constexpr const char *regnames[] { "Control", "Status", "Error register 1", "Maintenance", "Attention summary", "Desired sector/track address", "Look ahead", "Drive type", "Serial no", "Offset", "Desired cylinder address", "Current cylinder address", "Error register 2", "Error register 3", "ECC position", "ECC pattern" };
+constexpr const char *regnames[] { "Control", "Status", "Error register 1", "Maintenance", "Attention summary", "Desired sector/track address", "Error register 1", "Look ahead", "Drive type", "Serial no", "Offset", "Desired cylinder address", "Current cylinder address", "Error register 2", "Error register 3", "ECC position", "ECC pattern" };
 
 rp06::rp06(bus *const b, std::atomic_bool *const disk_read_activity, std::atomic_bool *const disk_write_activity) :
 	b(b),
@@ -38,6 +39,9 @@ void rp06::begin()
 
 void rp06::reset()
 {
+	memset(registers, 0x00, sizeof registers);
+
+	registers[reg_num(RP06_DS)] = default_DS;
 }
 
 void rp06::show_state(console *const cnsl) const
@@ -74,8 +78,12 @@ uint16_t rp06::read_word(const uint16_t addr)
 	const int reg   = reg_num(addr);
 	uint16_t  value = registers[reg];
 
+	if (addr == RP06_CS1)
+		value |= 0200 /* ready */;
+	else if (addr == RP06_DS)
+		value |= 0400 /* drive present */ | 010000 /* medium on-line */ | 0100 /* volume valid */ | 0200 /* drive ready */;
+
 	TRACE("RP06: read \"%s\"/%o: %06o", regnames[reg], addr, value);
-	printf("RP06: read \"%s\"/%o: %06o\r\n", regnames[reg], addr, value);
 
 	return value;
 }
@@ -90,11 +98,11 @@ void rp06::write_byte(const uint16_t addr, const uint8_t v)
 	uint16_t vtemp = registers[reg_num(addr)];
 
 	if (addr & 1) {
-		vtemp &= ~0xff00;
+		vtemp &= 0x00ff;
 		vtemp |= v << 8;
 	}
 	else {
-		vtemp &= ~0x00ff;
+		vtemp &= 0xff00;
 		vtemp |= v;
 	}
 
@@ -167,8 +175,7 @@ void rp06::write_word(const uint16_t addr, uint16_t v)
 
 				generate_interrupt = true;
 			}
-
-			if (function_code == 070) {  // READ
+			else if (function_code == 070) {  // READ
 				uint32_t offs = compute_offset();
 				uint32_t addr = getphysaddr();
 
@@ -192,7 +199,7 @@ void rp06::write_word(const uint16_t addr, uint16_t v)
 						b->writeUnibusByte(addr++, xfer_buffer[i]);
 				}
 
-				registers[reg_num(RP06_WC)] = 0;
+				registers[reg_num(RP06_WC)]   = 0;
 				registers[reg_num(RP06_CS1)] |= 0200;  // drive ready
 
 				generate_interrupt = true;
diff --git a/rp06.h b/rp06.h
index 724e1ae..f418714 100644
--- a/rp06.h
+++ b/rp06.h
@@ -22,6 +22,7 @@
 #define RP06_DA	 	0176706  // desired address
 #define RP06_CS2	0176710  // control/status register 2
 #define RP06_DS	 	0176712  // drive status
+#define RP06_ERRREG1    0176714  // error register 1
 #define RP06_AS	 	0176716  // unified attention status
 #define RP06_RMLA	0176720  // lookahead (sector under head!!)
 #define RP06_OFR	0176732  // heads offset