Load Cisco IOS on router from ROMMON

rommon 50 > IP_ADDRESS=192.168.2.20

rommon 51 >IP_SUBNET_MASK=255.255.255.0

rommon 52 >DEFAULT_GATEWAY=192.168.2.1

rommon 53 > TFTP_SERVER=192.168.2.7

rommon 54> TFTP_FILE=/private/tftpboot/"filename.bin"

rommon 55 >tftpdnld

Once Done issue reset command

rommon 56 > reset

Copy Cisco IOS from router to tftp Mac OSX

Install tftp server for Mac or enable tftp server using 

sudo launchctl load -w /System/Library/LaunchDaemons/tftp.plist 

Create file name  on server l

sudo touch /private/tftpboot/"filename.bin"

Change permission for the file 

sudo chmod a+w /private/tftpboot/"filename.bin"

On router type this command 

R1#copy flash: tftp:

Source filename [filename.bin]? 

Address or name of remote host []? 192.168.2.10      

Destination filename ["filename.bin"]? /private/tftpboot/"filename.bin"