I don't really know what the purpose of this module is.
The LED remains active in Stamina mode since I believe the 4.2. update for the Xperia Z in mid 2013 or even earlier in one of the newer 4.1. official firmwares...
The same goes for the Z1 and Z1 compact so there is really no need for it.
People don't even need root as it is active with stock Sony firmware.
Sony Xperia Z1 white (root, dualrecovery, lb, Android 4.4.2 KitKat (SD card fix), 120fps+4k mod, 64GB microSD)
Ericsson T65 ('01-'04) - NEC e616 ('04-'05) - Sony Ericsson K750i ('05-'06) - Samsung D830 ('06-'07) - Sony Ericsson K850i ('07-'10) - Nokia E51 ('10 - 2months) - Sony Ericsson Vivaz ('10-'11) - Sony Ericsson Xperia Arc ('11-'12) - Samsung Galaxy S2 ('12-'13) - Sony Xperia Z ('13) - Sony Xperia Z1 ('13-?)