Thanks @tekka, that worked!

I attached the bootloader for other interested people.

Settings:
CSN pin: 7
CE pin: 8

#define RF24_CHANNEL	   90             //RF channel for the sensor net, 0-127
#define RF24_DATARATE 	   RF24_250KBPS   //RF24_250KBPS for 250kbs, RF24_1MBPS for 1Mbps, or RF24_2MBPS for 2Mbps
#define RF24_PA_LEVEL 	   RF24_PA_MAX    //Sensor PA Level == RF24_PA_MIN=-18dBm, RF24_PA_LOW=-12dBm, RF24_PA_HIGH=-6dBM, and RF24_PA_MAX=0dBm
#define RF24_PA_LEVEL_GW   RF24_PA_LOW  //Gateway PA Level, defaults to Sensor net PA Level.  Tune here if using an amplified nRF2401+ in your gateway.
#define BASE_RADIO_ID 	   ((uint64_t)0xA8A8E1FC00LL) // This is also act as base value for sensor nodeId addresses. Change this (or channel) if you have more than one sensor network.

MYSBootloader.hex

Hello all,

I am trying to make a new bootloader where the CSN and CE pins are connected to pin 7 and 8. (CSN = 7 and CE = 8 ).

This is what I changed in the bootloader:

// SPI communication

#define SPI_DDR		DDRB
#define SPI_PORT	PORTB
#define SPI_PORT2   PORTD
#define SPI_PIN		PINB
#define	SPI_SCLK	5		// Arduino Pin 13 <-> Bit 5 of port B
#define	SPI_MISO	4		// Arduino Pin 12 <-> Bit 4 of port B
#define	SPI_MOSI	3		// Arduino Pin 11 <-> Bit 3 of port B
#define	SPI_CSN		7		// Arduino Pin 7 <-> Bit 7 of port D
//#define	SPI_CSN		2		// Arduino Pin 10 <-> Bit 2 of port B
#define	SPI_CE		0		// Arduino Pin  8 <-> Bit 0 of port B
//#define	SPI_CE		1		// Arduino Pin  9 <-> Bit 1 of port B
#define CE_PULSE_LENGTH	20	// IMPORTANT: minimum CE pulse width 10us, see nRF24L01 specs. Set 20us to be on the safe side

#define csnlow() DDRD &= ~_BV(SPI_CSN)
#define csnhigh() DDRD |= _BV(SPI_CSN)

#define celow() SPI_PORT &= ~_BV(SPI_CE)
#define cehigh() SPI_PORT |= _BV(SPI_CE)

static void SPIinit() {
	// set pin mode: MOSI,SCLK,CE = OUTPUT, MISO = INPUT
	SPI_DDR = _BV(SPI_MOSI) | _BV(SPI_SCLK) | _BV(SPI_CE) | ~_BV(SPI_MISO);
    // Set CSN = output
	DDRD = _BV(SPI_CSN);
}

I uploaded the firmware to an Arduino and want to connect it to another Arduino which is programmed with the Serial Gateway sketch.
For discovery of nodes I use the MYSController software on windows, this is working correctly as I can discover my temperature node (which is programmed via arduino with the normal arduino bootloader).

But I can't get it to work, am I missing something?
I checked the settings in MyConfig (channel, power etc) but these are the same on the serial gateway sketch and the bootloader.

Compiler output for bootloader:

"C:/Program Files (x86)/Arduino/hardware/tools/avr/bin/avr-gcc" -x c -mno-interrupts -funsigned-char -funsigned-bitfields -DF_CPU=16000000L -Os -fno-inline-small-functions -fno-split-wide-types -ffunction-sections -fdata-sections -fpack-struct -fshort-enums -mrelax -Wall -mmcu=atmega328p -c -std=gnu99 -MD -MP -MF "MYSBootloader.d" -MT"MYSBootloader.d" -MT"MYSBootloader.o"  -I../libraries/MySensors MYSB
ootloader.c -o MYSBootloader.o
In file included from MYSBootloader.c:44:0:
MYSBootloader.h:28:2: warning: no semicolon at end of struct or union [enabled by default]
  };
  ^
In file included from MYSBootloaderRF24.h:4:0,
                 from MYSBootloader.h:13,
                 from MYSBootloader.c:44:
MYSBootloaderHW.h:96:13: warning: 'uart_init' defined but not used [-Wunused-function]
 static void uart_init() {
             ^
MYSBootloaderHW.h:126:13: warning: 'put_int' defined but not used [-Wunused-function]
 static void put_int(uint8_t i) {
             ^
"C:/Program Files (x86)/Arduino/hardware/tools/avr/bin/avr-gcc" -nostartfiles -Wl,-s -Wl,-static -Wl,-Map=".map" -Wl,--start-group  -Wl,--end-group -Wl,--gc-sections -mrelax -Wl,-section-start=.text=0x7800 -mmcu=atmega328p   -o MYSBootloader.elf MYSBootloader.o -lm
"C:/Program Files (x86)/Arduino/hardware/tools/avr/bin/avr-objcopy" -O ihex -R .eeprom MYSBootloader.elf MYSBootloader.hex
"C:/Program Files (x86)/Arduino/hardware/tools/avr/bin/avr-size" MYSBootloader.elf
   text    data     bss     dec     hex filename
   2004       2     214    2220     8ac MYSBootloader.elf

Thanks for reading!

• Ruud