Here are the steps I have taken to install Shibby's 108 AIO build on a brand new ASUS RT-N16 from a Mac:
Combined Tutorial Installing On Asus Routers (RT-N16 etc) in Linux and forum post Installing On Asus Routers for Mac OS X
1. Downloaded the 108 AIO build of Shibby to the /Users/Drew/Downloads directory on my Mac
2. Use a cable to connect your computer to LAN port 1 on the router. FYI, this is a brand new router, straight from the box. Never operated before.
3. Turn off the router, disable your ethernet connection:
sudo ifconfig en0 down
4. Turn on the router while holding down the 'restore' button on the back. You should be rewarded with a flashing power LED.
5. Enable your network:
sudo ifconfig en0 up 192.168.1.2
6. Check you can ping your router.
PING 192.168.1.1 (192.168.1.1): 56 data bytes
64 bytes from 192.168.1.1: icmp_seq=0 ttl=100 time=2.606 ms
64 bytes from 192.168.1.1: icmp_seq=1 ttl=100 time=0.665 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=100 time=0.697 ms
7. Upload the firmware:
cd /Users/Drew/Downloads ls *.trx tomato-K26USB-1.28.RT-MIPSR1-108-AIO.trx tftp 192.168.1.1 tftp> binary tftp> put tomato-K26USB-1.28.RT-MIPSR1-108-AIO.trx
8. Then wait for the prompt to be returned, and wait for a further minute.
9. Finally turn off the router, set your ethernet back to auto, wait a minute, turn on the router and you should have a tomato install!
Source: Concentric Livers.
OK, at this point, I don't really know what "set your ethernet back to auto" means. man ifconfig does not list an "auto" switch. So I guess this means to go to DHCP on the Mac…? but I don't get an IP that makes any sense and I can't connect to 192.168.1.1. Just continue with manual network setting of 192.168.1.2, subnet mask 255.255.255.0, router 192.168.1.1.
So I continue reading…
Additional clarifications from Sergey Gleizer:
After TFTP session completes, wait about five minutes for the firmware to actually be flashed. There is no visual indicator that flashing is complete… If you fail to wait long enough before power cycling the router, it will have an incomplete firmare flash and will go to recovery mode (slow flashing power LED, same as when powering up with 'restore' button pressed)
After a successfull flash, it is a good idea to clear NVRAM by powering up while holding down WPS button and continuing to hold it for 30 sec after power-up.
I basically redo steps 2-7, then at step 8, change that to 5 minutes. Try to reconnect, and nothing.