Problem: HP LaserJet CP3525n refused to print black and white documents when one of the color cartridges was out of toner, despite “Color supplies out” setting was set to “Autocontinue black”.
Solution: go to Menu > Configure device > System setup and set “Replace supplies” to “Override at out 1“. Read the warning, set the limit and you’re done.
Please note that this setting is not available through web-configurator! (That was the tricky part for a lazy person like me). Use the printer’s menu.