Kali Linux Hash Sum Mismatch while doing apt update

https://askubuntu.com/questions/1235914/hash-sum-mismatch-error-due-to-identical-sha1-and-md5-but-different-sha256

Looks like the problem is caused by the Windows Hypervisor Platform. Work around is to disable it.

In the Start menu search for “turn Windows features on or off”

Once open, disable “Virtual Machine Platform” and “Windows Hypervisor Platform”

Disable Virtual Machine Platform

You will need to reboot after it finishes.

Ubiquiti U Installer Screenshots and Configuration Interface

By default the U Installer redirects you to a page asking you to download the app. You can get to the actual U Installer web page by going to https://169.254.169.169

Default U Installer Page
Access U Installer Certificate Error

It has the same interface as a regular Airmax M equipment.

U Installer main page

Unknown “Program” in Startup Programs – Windows 10

Which start up program is this? Did I install it???

Unknown Startup Program

Enabling the Command line view will show us the location of the executable. Right click on the Top Row and Check “Command line”

Enable Command line

From the Command line column we see that the program is Tomboy

Command line shows us the location of the executable

Notes on OLED on Linux

OLED screens have had issues on Linux. Main problem is unable to control the screen brightness. It looks like there are some ways to do it now

Looks like icc-brightness should help. Install instructions are from here

sudo apt install -y liblcms2-dev
git clone https://github.com/udifuchs/icc-brightness.git
cd icc-brightness
make

You can run the utility with

./icc-brightness

Installing it will set it up to automatically run on log in.

sudo make install

Log out and back in and it should work.

https://appaper.com/oled-laptop-screen-brightness-control-linux/
https://www.reddit.com/r/linux/comments/cmf0vi/the_state_of_oled_brightness_on_linux/

Android Button – Remove Shadow and Border from Button with Image on it

We can remove the border and shadows from a button by adding the following style code in your activity_main.xml file. Or what ever your XML file is.

style="?android:attr/borderlessButtonStyle"

Code for button. We are setting an image as the background.

  <Button
        android:id="@+id/button"
        style="?android:attr/borderlessButtonStyle"
        android:layout_width="48dp"
        android:layout_height="48dp"
        android:background="@drawable/gear"
        android:onClick="launchSettings"
        android:textSize="12sp"/>

Comparison of buttons. One on the left still has the shadow on it

Difference between border and borderless buttons

More info here

https://stackoverflow.com/questions/28756035/how-to-remove-button-shadow-android
https://stackoverflow.com/questions/27867284/remove-shadow-effect-on-android-button/30856094

UFW Allow ICMP (ping) Traffic

https://askubuntu.com/questions/6995/how-to-enable-ufw-firewall-to-allow-icmp-response

Open up the UFW before.rules config file

vi /etc/ufw/before.rules 

And make sure you have these rules in it

# ok icmp codes for INPUT
-A ufw-before-input -p icmp --icmp-type destination-unreachable -j ACCEPT
-A ufw-before-input -p icmp --icmp-type time-exceeded -j ACCEPT
-A ufw-before-input -p icmp --icmp-type parameter-problem -j ACCEPT
-A ufw-before-input -p icmp --icmp-type echo-request -j ACCEPT
# ok icmp code for FORWARD
-A ufw-before-forward -p icmp --icmp-type destination-unreachable -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type time-exceeded -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type parameter-problem -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type echo-request -j ACCEPT

Getting Android WiFi state in Kotlin

In Kotlin you can request if the WiFi adapter is on or off with the following code
This changes the text on a textbox, replace with your textbox.

wifiManager = this.applicationContext.getSystemService(Context.WIFI_SERVICE) as WifiManager
textBox.text = "WiFi State = ${wifiManager.wifiState}"

The important part is

wifiManager.wifiState

It will return a number from 0-4 which indicates if it is on or off.

0 = WiFi is being disabled
1 = WiFi Disabled
2 = WiFi is being enabled
3 = WiFi is Enabled
4 = Error

https://developer.android.com/reference/kotlin/android/net/wifi/WifiManager#WIFI_STATE_DISABLED:kotlin.Int

Cambium 450 Bandwidth PLL lock lost

Had a radio briefly showing an error in red on the web page saying “Bandwidth PLL lock lost” The radio seems to operate so not sure if it is an actual issue or maybe an ongoing bug.

Cambium Bandwidth PLL lock lost

These entries are from the cambium 16.1.1 Release Notes
https://community.cambiumnetworks.com/t/450-platform-series-release-16-1-1-is-now-available/65335

  • A very few 450i/450b SMs having “Bandwidth PLL lock lost” and being unable to register to AP on 20 and 30 MHz after upgrade to 16.1.
  • Occasional false positive of 450 radios was showing “Bandwidth PLL lock Lost” but operating normally.

https://community.cambiumnetworks.com/t/pmp450-sm-v16-1-error-bandwidth-pll-lock-lost/63243

Cannot load Zend OPcache – it was already loaded

Started getting the following error while running ./validate.php for LibreNMS

Cannot load Zend OPcache - it was already loaded

Looks like the problem arises out of PHP trying to load two ini files for OPcache. Was trying to enable OPcache for LibreNMS so I created an opcache.ini file and put the settings in it. I missed the default 10-opcache.ini file.

Moving all the settings into the 10-opcache.ini file and deleting the created opcache.ini file resolved the issue for me.

https://unix.stackexchange.com/questions/253448/php-7-install-throws-cannot-load-zend-opcache-it-was-already-loaded-error/253484