Unable to get I2C working on Raspberry-Pi-5

1)created sdcard.img using make raspberrypi5_defconfig

2)sdcard.img was written to micro-sdcard and able to boot the pi5 board

3)on pi5 console, ls /dev/i2c* did not show anything

4)on a running system, mounted /dev/mmcblk0p1 to /tmp/boot and added following lines to /tmp/boot/config.txt dtoverlay=i2c1,pins_2_3,baudrate=1000000 dtparam=i2c_arm=on

5)rebooted the board but /dev/i2c* didnt show anything

6)modified config.txt again with following changes but /dev/i2c* didnt show up. dtoverlay=i2c1-pi5 dtparam=i2c_arm=on

7)when booting pi-5 with RaspberryPi-OS and enabling the i2c using sudo raspi-config shows up three nodes under /dev/i2c*

Any idea what am I missing here? has anyone managed to get i2c working on a buildroot generated image for pi-5? what changes did u do in your config.txt?

Thanks.