C2800nm+adventerprisek9+mz+152+1+t+bin -

Yes, physically. The 2800 line typically uses standard CompactFlash cards. You can replace the 64 MB card with a 256 MB or 512 MB CF card. Format it as FAT16 or FAT32 before inserting.

Yes, but not for the 2800. The final release for the 2800 was 15.2(4)M6. However, 15.2(4)M is a "Mainline" release (more stability, fewer features). 15.2(1)T has more features; 15.2(4)M has more bug fixes. For most users, 15.2(4)M6 is actually better, though the filename structure differs. c2800nm+adventerprisek9+mz+152+1+t+bin

To load this image (via ROMMON or existing IOS): Yes, physically

Router(config)# boot system flash:c2800nm-adventerprisek9-mz.152-1.T.bin
Router(config)# config-register 0x2102
Router# write memory
Router# reload

If flash lacks space, the image can be loaded over TFTP from ROMMON: Yes, but not for the 2800

rommon 1> IP_ADDRESS=192.168.1.10
rommon 2> DEFAULT_GATEWAY=192.168.1.1
rommon 3> TFTP_SERVER=192.168.1.100
rommon 4> FILE_NAME=c2800nm-adventerprisek9-mz.152-1.T.bin
rommon 5> tftpdnld

The k9 designation signifies strong encryption, subject to U.S. export controls under EAR. Supported algorithms:

Without the K9 image, the standard image limited encryption to 56-bit DES (weak by modern standards).

Cisco IOS filenames are not random; they follow a strict naming convention. Understanding c2800nm-adventerprisek9-mz.152-1.T.bin is crucial for any engineer.