[G3 Developer Discussion [Developers Only]] Kickoff:
Vector codes

REAL SOLUTION

Since the release of 20H software version LG also introduced the Lollipop navbar icons. These are defined in LGSystemUI.apk res/drawables folder by xml files ic_sysbar_@_button.xml where @ is the corresponding function name (for example ic_sysbar_back_button.xml.

Back button:

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M122.132,132c-0.921,0-1.759-0.324-2.435-0.847L44.916,87.979c-0.965-0.499-1.956-0.894-2.525-1.88c-0.338-0.586-0.492-1.221-0.516-1.852c-0.007-0.082-0.004-0.165-0.007-0.247c0.003-0.082,0-0.165,0.007-0.247c0.023-0.632,0.178-1.266,0.516-1.852c0.569-0.987,1.623-1.35,2.525-1.88l74.781-43.175c0.676-0.523,1.514-0.847,2.435-0.847c2.209,0,4,1.791,4,4v88C126.132,130.209,124.341,132,122.132,132zM54.025,84l64.106,37.012V46.988L54.025,84z" />
</vector>

Dual window

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M120,36H48c-6.627,0-12,5.373-12,12v72c0,6.627,5.373,12,12,12h72c6.627,0,12-5.373,12-12V48C132,41.373,126.627,36,120,36zM124,120c0,2.209-1.791,4-4,4H48c-2.209,0-4-1.791-4-4V88h80V120zM124,80H44V48c0-2.209,1.791-4,4-4h72c2.209,0,4,1.791,4,4V80z" />
<path android:fillColor="#ffffffff" android:pathData="M85.871,73.958h-4.795V55.041H76.23v-3.065l9.641-2.01V73.958z" />
<path android:fillColor="#ffffffff" android:pathData="M92.177,118.375h-16.38v-3.147l7.762-8.322c1.143-1.307,1.944-2.395,2.406-3.263c0.461-0.868,0.691-1.687,0.691-2.455c0-1.033-0.267-1.865-0.799-2.497c-0.533-0.632-1.31-0.947-2.332-0.947c-1.131,0-1.979,0.371-2.545,1.112c-0.566,0.741-0.85,1.75-0.85,3.023h-4.812c0-2.252,0.73-4.122,2.192-5.61c1.461-1.489,3.465-2.233,6.014-2.233c2.516,0,4.469,0.632,5.858,1.896s2.085,2.988,2.085,5.174c0,1.473-0.388,2.808-1.162,4.005s-2.101,2.807-3.979,4.828l-4.351,4.746h10.2V118.375z" />
</vector>

Home button

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M84,131.916c-26.464,0-47.917-21.453-47.917-47.916c0-26.463,21.453-47.917,47.917-47.917S131.917,57.537,131.917,84C131.917,110.465,110.463,131.916,84,131.916zM84,44.333c-21.908,0-39.667,17.76-39.667,39.667c0,21.908,17.76,39.667,39.667,39.667s39.667-17.76,39.667-39.667C123.667,62.093,105.908,44.333,84,44.333z" />
</vector>

Menu button

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M40,54h88c2.209,0,4-1.791,4-4s-1.791-4-4-4H40c-2.209,0-4,1.791-4,4S37.791,54,40,54zM128,80H40c-2.209,0-4,1.791-4,4s1.791,4,4,4h88c2.209,0,4-1.791,4-4S130.209,80,128,80zM128,114H40c-2.209,0-4,1.791-4,4s1.791,4,4,4h88c2.209,0,4-1.791,4-4S130.209,114,128,114z" />
</vector>

Notification down

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M123,44.179H45c-2.209,0-4-1.791-4-4s1.791-4,4-4h78c2.209,0,4,1.791,4,4S125.209,44.179,123,44.179zM51.181,90.828L79,118.647V58.379c0-2.209,1.791-4,4-4s4,1.791,4,4v60.557l28.025-28.026c1.563-1.562,4.096-1.562,5.656,0c1.563,1.563,1.563,4.096,0,5.658L86.59,130.66c-1.018,1.018-2.445,1.359-3.75,1.052c-1.151,0.114-2.342-0.253-3.224-1.134L45.524,96.486c-1.562-1.563-1.562-4.096,0-5.658C47.086,89.267,49.619,89.267,51.181,90.828z" />
</vector>

Notification up

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M123,131.82H45c-2.209,0-4-1.791-4-4s1.791-4,4-4h78c2.209,0,4,1.791,4,4S125.209,131.82,123,131.82zM115.025,77.09L87,49.064v60.556c0,2.209-1.791,4-4,4s-4-1.791-4-4V49.354L51.181,77.172c-1.562,1.563-4.095,1.563-5.657,0c-1.562-1.562-1.562-4.095,0-5.657l34.092-34.092c0.882-0.882,2.073-1.248,3.224-1.134c1.305-0.309,2.733,0.034,3.75,1.052l34.092,34.092c1.563,1.562,1.563,4.095,0,5.657C119.121,78.652,116.588,78.652,115.025,77.09z" />
</vector>

Qmemo button

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M87.637,123.2c-19.2,0-43.168,0-43.168,0c-5.523,0-10-4.478-10-10v-66c0-5.523,4.477-10,10-10h66c5.522,0,10,4.477,10,10c0,0,0,23.578,0,42.833c0,7.74-0.167,1.55-0.167,3.667c0,2.116-1.716,3.833-3.833,3.833s-3.832-1.717-3.832-3.833c0-2.117-0.168,1.901-0.168-3.5c0-16.292,0-39,0-39c0-3.313-2.687-6-6-6h-58c-3.313,0-6,2.687-6,6v58c0,3.313,2.688,6,6,6c0,0,22.708,0,39,0c5.402,0-0.117,0.237,2,0.237s3.833,1.717,3.833,3.834s-1.716,3.834-3.833,3.834S95.198,123.2,87.637,123.2z" />
<path android:fillColor="#ffffffff" android:pathData="M102.559,110.938c-3.443-3.053-8.367-8.672-10.938-12.484l-2.563-3.801c-2.572-3.813-1.324-5.215,2.772-3.113l4.082,2.094c4.098,2.102,10.269,6.319,13.711,9.372l22.323,18.669c1.951,1.73,2.128,4.713,0.395,6.661l-0.783,0.881c-1.734,1.947-4.723,2.124-6.675,0.394L102.559,110.938z" />
</vector>

Qslide button

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M98,74h26c2.209,0,4-1.791,4-4s-1.791-4-4-4h-16.302l19.515-19.515c1.563-1.562,1.563-4.095,0-5.657c-1.563-1.563-4.095-1.563-5.656,0L102,60.385V44c0-2.209-1.791-4-4-4s-4,1.791-4,4v26C94,72.209,95.791,74,98,74z" />
<path android:fillColor="#ffffffff" android:pathData="M70,94H44c-2.209,0-4,1.791-4,4s1.791,4,4,4h16.301l-19.515,19.516c-1.562,1.563-1.562,4.094,0,5.656c1.563,1.563,4.095,1.563,5.657,0L66,107.615V124c0,2.209,1.791,4,4,4s4-1.791,4-4V98C74,95.791,72.209,94,70,94z" />
<path android:fillColor="#ffffffff" android:pathData="M107.698,102H124c2.209,0,4-1.791,4-4s-1.791-4-4-4H98c-2.209,0-4,1.791-4,4v26c0,2.209,1.791,4,4,4s4-1.791,4-4v-16.385l19.557,19.557c1.563,1.563,4.096,1.563,5.656,0c1.563-1.563,1.563-4.095,0-5.656L107.698,102z" />
<path android:fillColor="#ffffffff" android:pathData="M70,40c-2.209,0-4,1.791-4,4v16.385L46.443,40.829c-1.562-1.563-4.094-1.563-5.657,0c-1.562,1.562-1.562,4.095,0,5.657L60.301,66H44c-2.209,0-4,1.791-4,4s1.791,4,4,4h26c2.209,0,4-1.791,4-4V44C74,41.791,72.209,40,70,40z" />
</vector>

Recent button

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M128.041,36.042H39.958c-2.209,0-4,1.791-4,4v87.917c0,2.209,1.791,4,4,4h88.083c2.211,0,4-1.791,4-4V40.042C132.041,37.833,130.252,36.042,128.041,36.042zM123.791,123.041c0,0.553-0.447,1-1,1H44.792c-0.553,0-1-0.447-1-1v-78c0-0.552,0.447-1,1-1h77.999c0.553,0,1,0.448,1,1V123.041z" />
</vector>

Simswitch button

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="34.0dip" android:width="34.0dip" android:viewportWidth="168.0" android:viewportHeight="168.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#ffffffff" android:pathData="M137.348,121.033h-54.71c-2.569,0-4.653-2.09-4.653-4.668V94.984h-14.7l3.836,3.852c1.558,1.563,1.558,4.096,0,5.656c-0.779,0.781-1.799,1.172-2.82,1.172s-2.042-0.391-2.82-1.172l-10.368-10.41c-1.558-1.563-1.558-4.094,0-5.654l10.369-10.406c1.558-1.563,4.082-1.563,5.64,0c1.558,1.562,1.558,4.095,0,5.656l-3.272,3.285h17.501c2.569,0,4.653,2.09,4.653,4.666v21.352h48.004V67.817l-14.582-12.892H91.881c-2.57,0-4.279-1.465-4.279-4.042c0-2.577,1.709-3.917,4.279-3.917h28.49c1.135,0,2.229,0.416,3.078,1.167l16.979,15.08c1,0.885,1.572,2.16,1.572,3.499v49.653C142,118.943,139.918,121.033,137.348,121.033zM89.988,66.711v6.292h14.457l-3.563-3.576c-1.559-1.561-1.559-4.095,0-5.656c1.559-1.563,4.082-1.563,5.641,0l10.367,10.405c1.559,1.562,1.559,4.094,0,5.656L106.523,90.24c-0.777,0.781-1.801,1.172-2.82,1.172s-2.041-0.391-2.818-1.172c-1.559-1.563-1.559-4.094,0-5.656l3.662-3.677H86.654c-2.569,0-4.653-2.09-4.653-4.667v-8.509L67.605,54.963H33.993v58.017h31.566c2.569,0,4.153,1.434,4.153,4.01s-1.584,4.012-4.153,4.012H30.653c-2.569,0-4.653-2.09-4.653-4.668V51.633c0-2.577,2.083-4.667,4.653-4.667h37.644c1.133,0,2.228,0.416,3.078,1.167l17.04,15.08C89.414,64.098,89.988,65.373,89.988,66.711z" />
</vector>

For all button there is a different code for the transparent version. The above codes are already modified by me because the stock buttons are way too big. See here.

The button size is defined by vector android:height="42.0dip" android:width="42.0dip" and I decreased those values for my Lollipop theme.

In ChupaChups 4.1 you will be able to reduce the navigation bar height which requires the change of the corresponding button height as well.

I hope I helped. Good work with this icons.