raspi3 image on raspi2:
ubuntu@raspi3:~$ sudo dmesg | grep -i -e serial -e tty -e console -e uart
[sudo] password for ubuntu:
[ 0.000000] Kernel command line: dma.dmachans=0x7f35 bcm2708_fb.fbwidth=656 bcm2708_fb.fbheight=416 bcm2709.boardrev=0xa01041 bcm2709.serial=0xa52da1ca smsc95xx.macaddr=B8:27:EB:2D:A1:CA bcm2708_fb.fbswap=1 bcm2709.uart_clock=3000000 bcm2709.disk_led_gpio=47 bcm2709.disk_led_active_low=0 vc_mem.mem_base=0x3dc00000 vc_mem.mem_size=0x3f000000 dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
[ 0.000354] Console: colour dummy device 80x30
[ 0.001551] console [tty1] enabled
[ 0.101010] Serial: AMBA PL011 UART driver
[ 0.101355] 3f201000.uart: ttyAMA0 at MMIO 0x3f201000 (irq = 87, base_baud = 0) is a PL011 rev2
[ 0.639879] console [ttyAMA0] enabled
[ 1.081225] Console: switching to colour frame buffer device 82x26
[ 2.499121] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 2.522401] usb usb1: SerialNumber: 3f980000.usb
[ 3.241967] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 3.441932] uart-pl011 3f201000.uart: no DMA platform data
[ 3.672299] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 3.784112] systemd[1]: Started Dispatch Password Requests to Console Directory Watch.
[ 3.820498] systemd[1]: Created slice system-serial\x2dgetty.slice.
[ 3.985301] systemd[1]: Created slice system-getty.slice.
ubuntu@raspi3:~$
raspi2 image on raspi2:
ubuntu@raspi2:~$ sudo dmesg | grep -i -e serial -e tty -e console -e uart
[ 0.000000] Kernel command line: dma.dmachans=0x7f35 bcm2708_fb.fbwidth=656 bcm2708_fb.fbheight=416 bcm2709.boardrev=0xa01041 bcm2709.serial=0xa52da1ca smsc95xx.macaddr=B8:27:EB:2D:A1:CA bcm2708_fb.fbswap=1 bcm2709.uart_clock=3000000 bcm2709.disk_led_gpio=47 bcm2709.disk_led_active_low=0 vc_mem.mem_base=0x3dc00000 vc_mem.mem_size=0x3f000000 dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
[ 0.000403] Console: colour dummy device 80x30
[ 0.001567] console [tty1] enabled
[ 0.102626] Serial: AMBA PL011 UART driver
[ 0.102977] 3f201000.uart: ttyAMA0 at MMIO 0x3f201000 (irq = 87, base_baud = 0) is a PL011 rev2
[ 0.640759] console [ttyAMA0] enabled
[ 1.082258] Console: switching to colour frame buffer device 82x26
[ 2.503693] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 2.527022] usb usb1: SerialNumber: 3f980000.usb
[ 3.132891] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 3.553917] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 3.581943] uart-pl011 3f201000.uart: no DMA platform data
[ 4.097760] systemd[1]: Created slice system-getty.slice.
[ 4.153102] systemd[1]: Created slice system-serial\x2dgetty.slice.
[ 4.321121] systemd[1]: Started Dispatch Password Requests to Console Directory Watch.
ubuntu@raspi2:~$