In Airplane Mode the device last noticably longer. The "Cell standby" shows 76% in battery settings.
There are two SIM cards inserted into the device, but now I use only the second. I expect that if I disable the first SIM card, it should consume less power. I don't want to put it away from the slow although, as it's easy to lost or forget about it when needed.
How do I disable (as in "Airplane mode") only one of two SIM cards on Android? If there is no proper way, can it be done by some root trick?