The IOS that was shipped with of our Cisco 2901 was some how deleted.
I got another IOS (c2900-universalk9-mz.SPA.157-3.M4a) but I am not able to upload.
I tried XMODEM, but it was not transferred.
I tried using a good USB(4GB FAT file system), but the router would not recognize the USB.
I tired using tftpd64, I did not make a headway.
I removed the flash and put it in a Cisco 1901 , but I still cannot upload IOS to the flash.