Editing Apple LaserWriter II NTX (section)

=== ROM upgrade to revision 3.0 ===
Apple's NTX ROM upgrade adds software switching between PostScript and the Diablo 630 and LaserJet emulations on the LocalTalk port, support for several hard disks and for disks over 40 MB, and extra characters in LaserJet mode.<ref name="ss" /> The procedure:<ref name="ss" /><ref name="asg" />
# Switch off and unplug the printer. Wear an earthed wrist strap.
# Remove the I/O board and lay it on an earthed mat.
# Lift the eight ROMs (HH0, HH1, HM0, HM1, LL0, LL1, LM0, LM1) with an IC extractor.
# Fit the new ROMs. The marking at the end of the first line printed on each chip matches its socket; the ROMs are not interchangeable. The notch of each ROM faces the connector panel.
# Refit the board, switch on and wait about 3 minutes for the startup page. The PostScript version is printed at the end of the first line of the copyright text along the right edge; it should read rev 3.0.
# If no startup page appears, check the ROMs are seated and run the NT/NTX ROM and SIMM test, or swap in known-good ROMs.

The LaserWriter Font Utility version 2.0 or later is needed to initialise a printer hard disk on an NTX with revision 3.0 ROMs.<ref name="asg" />