RFU Load Error Resend RFU Message On HP LaserJet 4240 4250 4350..

An RFU file is a Remote Firmware Update file.  If you see error messages like this -"RFU Load Error" or "Resend RFU" -- it means there is something wrong with the firmware, and usually refers to the fact that a firmware update was not successful. 

As a side note, in general we don't see much value in firmware updates so we don't recommend end users perform firmware updates unless absolutely necessary.  Very occasionally we will turn a problem that can be resolved with a firmware update, but it's a rare case.   Also firmware updates can be a bit complicated and the file transfer can fail; so we don't recommend you do firmware updates unless necessary.  because they can fail and leave error messages like this. 

Try sending another firmware update

Again, we're not big advocates for sending firmware updates, but sometimes resending a fresh firmware update will clear these messages.  There are 2 or 3 ways to send a firmware upgrade, via parallel port, USB port, or network port/FTP.   Sometimes resending the firmware update through a different port works, sometimes it doesn't help at all. 

Try setting the printer to "Ignore RFU messages" , use the following steps.

• Turn the printer off and back on.
• As soon as the memory count begins, hold down the Stop button until all three control panel lights flash once and then remain lit.
• Press the Checkmark button, then press the Menu button.
• Press the Down arrow repeatedly until you see “Clear All RFU Errors”.
• Press the Checkmark button twice until the letter C is highlighted.
• Press the Down arrow until you see “Set Run mode to Manual”.
• Press the Checkmark button once so that the letter R is highlighted.
• Press the Down arrow until you see “Set RFU Error Off”.
• Press the Checkarm button twice until the letter S is highlighted.
• Next, turn the printer off and back on.
• Wait for the printer comes to Ready mode.
• At this point you can resume normal printing, or if you're ambitious you can try resending the firmware update.

• If nothing else works...Follow the final step

The last step is replacing the formatter assembly, which is the main logic board in these HP LaserJet printers.  Fortunately, replacing the formatter is very easy to do on these models.