%% Non-volatile configuration memory is being accessed, Try again later

If you get the error message,
%% Non-volatile configuration memory is being accessed, Try again later

while executing "show startup-config", is because another user is connected to the same router and has issued "show conf" but hasn't still completed.

You can find out who the connected user is by issuing "show users" or "who" command.

Upload IOS from ROMMon mode

Here is the steps to follow when you want to upload an IOS to your Cisco router from ROMMon mode:

You need to run the TFTP server on your PC. Connect your PC to LAN port of your router, configure your PC with the IP address which is assigned to the TFTP server (192.168.16.19 in this example) and type the following commands: