Dell Latitude E6420: mouse not operational

Tested on: 0.4.7 BootCD, 0.4.9-dev-39-gd287d14 LiveCD and BootCD

Mousepad, mousepointer and external mouse not operational on a Dell Latitude E6420. External USB mouse does not seem to be powered.

Tried "the usual "Dell Latitude" hack, as in 8ea4200", "overwrite a model string directly in i8042prt.sys" (Serge Gautherie) in the installed file, but did not find searching it in Editor, I doubt Wordpad leaves the .sys file in a good shape and had not enough rights to save the file. Cannot compile myself.

Edit: Same happens on an Dell Latitude E5410 with above LiveCD.