I got an old HP Procurve Switch and wanted to upgrade the firmware.
After booting the switch, we configure the serial link to an Baudrate of 115200, so we won't have to wait all-night for the update to finish.


config
console baud-rate 115200
exit
write memory
reload


After reloading the switch and configuring our terminal software to 115200 baud, we can start the XModem Upload via:


copy xmodem flash primary


After that command, the switch waits for an XModem datatransfer to beginn. So, just upload your new firmware image via your terminal software, using XModem.

Another reload after copying the image will complete the setup.