To make a back up of the ROM of your HP48G Series Using Kermit,

1-Type :IO:name of the back up file
2-Press  [MEMORY] [NXT] [ARCHI]

Example:
Making a back up of my HP48GX HOME directory
I will call the back up file as BKGX.

Follow the steps  below:

1-Runs Kermit and set it in SERVER mode
2- type :IO:BKGX, in HP48
3-  [ MEMORY ] [NXT] [ARCHI]
4- It will show a pic like this below.

5- Kermit will tell you when transfer is complete.