The HP LaserJet M604 is a monochrome laser-based device that was designed off the HP LaserJet Enterprise M601, M602, M603 series engines. This series of printer models include the M604, M605 and M606.
This HP laser printer was designed as a replacement of the M601 series. It has features such as HP’s SureSmart, White listing and Run Time Intrusion Detection, all security features implemented in the 3.7 Firmware Versions or newer.
The difference of this design is the Embedded Multi Media Card (eMMC). This is a small circuit board located on the printer's Formatter. The eMMC stores the firmware in the event of a catastrophic formatter error. If a failure at the eMMC is detected, the printer will broadcast a 99.09.06 error code. The display will also read “no boot device”.
The eMMC is located on the Printer's Formatter near the top just to the left of the heat sink. The chip blends into the Formatter making it a bit difficult to locate. When replacing the eMMC, insert it onto the Formatter using two fingers and push it in straight as not to damage the connector or eMMC.
If replacing the Printer's Formatter for any reason, remove the eMMC from the defective board and install it onto the new Formatter. A firmware update may be required to be performed. The firmware version for the M604, M605 and M606 is 3.9.4 Date Code of Jan 2019. This is a bundle file version whereas the firmware must be loaded onto a flash
drive in the root directory.
If the error code 33.05 is displayed once inserting the eMMC and or replacing the Printer's Formatter, an updated firmware must be performed. The printer may broad cast this error along with the “Security Alert” message.
To perform a Printer Firmware update, press the power button and continue to tap-on the “Stop” or “Cancel” button in order to initiate the blue “Administration” screen. From there, select “Administrator” and insert the flash drive into the port under the control panel.
Once inserted select “USB Thumbdrive” option on the display. Once selected, the printer will display the Select File option. It should automatically highlight the correct Firmware version if copied onto the drive correctly.