diff --git a/src/cpu.c b/src/cpu.c
index d2151f8..23bf9c1 100644
--- a/src/cpu.c
+++ b/src/cpu.c
@@ -6,8 +6,11 @@
 
 void cpu_init(void)
 {
+	/* XXX an associated macro is checked, not the function */
+#ifdef clock_prescale_get
 	/* Disable clock division */
 	clock_prescale_set(clock_div_1);
+#endif
 }
 
 void cpu_reset(void)
diff --git a/src/global_commands.h b/src/global_commands.h
index 8909f50..6cb76bd 100644
--- a/src/global_commands.h
+++ b/src/global_commands.h
@@ -8,7 +8,7 @@ typedef BOOL (*global_command_func_t)(const uint8_t *tok_start, const uint8_t *l
 
 typedef struct
 {
-    const prog_char *name;
+    const char *name;
     global_command_func_t handler;
 } global_command_t;
 
diff --git a/src/hw_i2c.c b/src/hw_i2c.c
index 8ed2ad1..21b15ec 100644
--- a/src/hw_i2c.c
+++ b/src/hw_i2c.c
@@ -49,16 +49,7 @@
 
 #else
 
-#if __AVR_ATmega168__
-#define SDA             PC4        // SDA pin
-#define SCL             PC5        // SCL pin
-#define SDA_DDR         DDRC
-#define SCL_DDR         DDRC
-#define SDA_OUT         PORTC
-#define SCL_OUT         PORTC
-#define SDA_IN          PINC
-#define SCL_IN          PINC
-#elif __AVR_ATmega328P__
+#if __AVR_ATmega8__ || __AVR_ATmega168__ || __AVR_ATmega328P__
 #define SDA             PC4        // SDA pin
 #define SCL             PC5        // SCL pin
 #define SDA_DDR         DDRC
diff --git a/src/hw_spi.c b/src/hw_spi.c
index 60a4767..d68817f 100644
--- a/src/hw_spi.c
+++ b/src/hw_spi.c
@@ -3,7 +3,7 @@
 
 void hw_spi_init(void)
 {
-    uint8_t tmp;
+    uint8_t tmp __attribute__ ((unused)); /* used to discard status */
 
     // SCK and MOSI as output, SS as output - we're master
     SPI_DDR |= _BV(SPI_SCLK) | _BV(SPI_MOSI) | _BV(SPI_SS);
diff --git a/src/hw_spi.h b/src/hw_spi.h
index c3b3b44..25033cf 100644
--- a/src/hw_spi.h
+++ b/src/hw_spi.h
@@ -3,14 +3,7 @@
 
 #include <avr/io.h>
 
-#if __AVR_ATmega168__
-#define SPI_PORT    PORTB
-#define SPI_DDR     DDRB
-#define SPI_SS      PB2
-#define SPI_MOSI    PB3
-#define SPI_MISO    PB4
-#define SPI_SCLK    PB5
-#elif __AVR_ATmega328P__
+#if __AVR_ATmega8__ || __AVR_ATmega168__ || __AVR_ATmega328P__
 #define SPI_PORT    PORTB
 #define SPI_DDR     DDRB
 #define SPI_SS      PB2
diff --git a/src/hw_uart.c b/src/hw_uart.c
index 7cb5a37..6401ff2 100644
--- a/src/hw_uart.c
+++ b/src/hw_uart.c
@@ -6,27 +6,32 @@
 #include "console.h"
 #include "watchdog.h"
 
-// When doing calculations per page 174 od atmega168 datasheet,
-// make sure we use real numbers and round, not truncate
-#define UBRR_VAL ((1.0 * F_CPU / (16.0 * BAUD)) + 0.5 - 1)
-#define UBRR_DOUBLESPEED_VAL ((1.0 * F_CPU / (8.0 * BAUD)) + 0.5 - 1)
+#include <util/setbaud.h>       /* BAUD may be defined in hw_uart.h */
 
 void hw_uart_init(void)
 {
-#if __AVR_ATmega168__
-#if BAUD > 57600
-    // Setup lower divider to get higher precision for high baud rate.
+#if __AVR_ATmega168__ || __AVR_ATmega328P__
+#if USE_2X
     UCSR0A |= _BV(U2X0);
-    UBRR0 = UBRR_DOUBLESPEED_VAL;
 #else
-    UBRR0 = UBRR_VAL;
+    UCSR0A &= ~_BV(U2X0);
 #endif
+    UBRR0 = UBRR_VALUE;
     UCSR0B = _BV(TXEN0) | _BV(RXEN0);
-#elif __AVR_ATmega328P__
-    UBRR0 = (F_CPU / (16UL * BAUD)) - 1;
-    UCSR0B = _BV(TXEN0) | _BV(RXEN0);
+#elif __AVR_ATmega8__
+#if USE_2X
+    UCSRA |=  _BV(U2X);
+#else
+    UCSRA &= ~_BV(U2X);
+#endif
+    UBRRH = UBRRH_VALUE;
+    UBRRL = UBRRL_VALUE;
+    UCSRB = _BV(TXEN) | _BV(RXEN);
 #elif __AVR_AT90USB162__
-    UBRR1 = UBRR_VAL;
+#if USE_2X
+#error U2X not supported on AT90USB162
+#endif
+    UBRR1 = UBRR_VALUE;
     UCSR1B = _BV(TXEN1) | _BV(RXEN1);
 #else
 #error Unsupported device, FIXME
@@ -36,16 +41,15 @@ void hw_uart_init(void)
 void hw_uart_tick(void)
 {
 #ifdef CONFIG_HW_UART_CONSOLE
-#if __AVR_ATmega168__
+#if __AVR_ATmega168__ || __AVR_ATmega328P__
     if ((UCSR0A&(1<<RXC0)) != 0)
     {
         uint8_t c = UDR0;
         console_rx_callback(c);
     }
-#elif __AVR_ATmega328P__
-    if ((UCSR0A&(1<<RXC0)) != 0)
-    {
-        uint8_t c = UDR0;
+#elif __AVR_ATmega8__
+    if ((UCSRA&(1<<RXC)) != 0) {
+        uint8_t c = UDR;
         console_rx_callback(c);
     }
 #elif __AVR_AT90USB162__
@@ -62,14 +66,14 @@ void hw_uart_tick(void)
 
 void hw_uart_putc(char c)
 {
-#if __AVR_ATmega168__
+#if __AVR_ATmega168__ || __AVR_ATmega328P__
     while (bit_is_clear(UCSR0A, UDRE0))
         watchdog_reset();
     UDR0 = c;
-#elif __AVR_ATmega328P__
-    while (bit_is_clear(UCSR0A, UDRE0))
+#elif __AVR_ATmega8__
+    while (bit_is_clear(UCSRA, UDRE))
         watchdog_reset();
-    UDR0 = c;
+    UDR = c;
 #elif __AVR_AT90USB162__
     while (bit_is_clear(UCSR1A, UDRE1))
         watchdog_reset();
diff --git a/src/led.c b/src/led.c
index 13f1e77..334e1e9 100644
--- a/src/led.c
+++ b/src/led.c
@@ -86,7 +86,7 @@ static const uint8_t led_seq_glow[] PROGMEM =
 };
 
 
-static const uint8_t *led_sequences[] PROGMEM =
+static const uint8_t *const led_sequences[] PROGMEM =
 {
     [LED_SEQ_OFF] = led_seq_off,
     [LED_SEQ_ON] = led_seq_on,
diff --git a/src/menu.c b/src/menu.c
index d4bec38..7f2869e 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -21,7 +21,7 @@ MENU
 enum { MENU };
 #undef X
 #define X(sym,str) sym##_str,
-const uint8_t *my_menu[] PROGMEM = { MENU NULL };
+const uint8_t *const my_menu[] PROGMEM = { MENU NULL };
 #endif
 /*****************************************************************/
 #if 1
@@ -42,7 +42,7 @@ MY_MENU2
 enum { MY_MENU2 };
 #undef X
 #define X(sym,str) sym##_str,
-const uint8_t *my_menu2[] PROGMEM = { MY_MENU2 NULL };
+const uint8_t *const my_menu2[] PROGMEM = { MY_MENU2 NULL };
 
 /*****************************************************************/
 #endif
@@ -56,7 +56,7 @@ static void menu_print_item(uint8_t index, const uint8_t *str_P)
     console_newline();
 }
 
-uint8_t menu_show(const uint8_t **menu_P)
+uint8_t menu_show(const uint8_t *const *menu_P)
 {
     const uint8_t *str_P;
     uint8_t index = 0;
diff --git a/src/menu.h b/src/menu.h
index 4b1b377..7f9a1bb 100644
--- a/src/menu.h
+++ b/src/menu.h
@@ -1,7 +1,7 @@
 #ifndef MENU_H
 #define MENU_H 1
 
-uint8_t menu_show(const uint8_t **menu_P);
+uint8_t menu_show(const uint8_t *const *menu_P);
 uint8_t menu_pick_key(uint8_t max);
 
 void mymenu(void);
diff --git a/src/tick.c b/src/tick.c
index 190a94b..4d7facd 100644
--- a/src/tick.c
+++ b/src/tick.c
@@ -15,6 +15,15 @@ ISR(TIMER0_OVF_vect)
 void tick_init(void)
 {
     // setup clock divider. Timer0 overflows on counting to 256
+#if __AVR_ATmega8__
+    TCCR0 |= _BV(CS00);
+    TIFR  |= _BV(TOV0);
+
+    TCNT0  = 0x0;
+
+    // enable overflow interrupts
+    TIMSK |= _BV(TOIE0);
+#else
     TCCR0B |= _BV(CS00);
     TIFR0 |= _BV(TOV0);
 
@@ -22,6 +31,7 @@ void tick_init(void)
 
     // enable overflow interrupts
     TIMSK0 |= _BV(TOIE0);
+#endif
 }
 
 uint32_t tick_get(void)