HP LaserJet P2055dn - Manual (Page 99)

6. Hold the DIMM at a 45-degree angle, and then push the upper contacts of the DIMM firmly into the
slot. Make sure that the locks on each side of the DIMM snap into place.
CAUTION: Pressing the DIMM straight down will damage the contact pins.
NOTE: To remove a DIMM, first release the locks.
ENWW Install memory 87