Friday, June 8, 2018

Firefox: getting user-agent

I used to get my Firefox user-agent string through about: But in the recent version of Firefox, about: is no longer available. Instead, the user-agent can now be found under about:support

Ref:
Page "about:" removed in Firefox 59? | Firefox Support Forum | Mozilla Support

Tuesday, June 5, 2018

Kindle E-reader: disable screensaver

* only tested with a Kindle Keyboard

The power button of my Kindle Keyboard stopped working all the sudden. When I toggle it, it doesn't go into sleep mode. After leaving it idle for awhile, it went into sleep mode automatically. However, I can't turn it back on!!

Interestingly, the power button is not completely broken. I managed to reset the device by holding the power button for 30 seconds. Once it finish reboot, everything (except the power button) continue to work. As a workaround, I disabled the screensaver so I don't need to turn it ON/OFF again.

1. press Home
2. press ↵ (the enter key)
3. a search bar would appear
4. enter ;debugOn
5. enter ~disableScreensaver
6. enter ;debugOff

If you change your mind, replace step 5 with the following command:

~resumeScreensaver

Ref:
How To Turn Off The Kindle Screensaver – Permanently | IT Support Forum

Thursday, February 22, 2018

Win10: PC wakes up randomly overnight

Last week, I was troubleshooting an issue where my PC starts waking up randomly overnight. Sometimes, it would wake up immediately after going into hibernation.

Apparently I was not alone. Kirk Hamilton from kotaku ran into the same issue as well, and he wrote an article about it. Funny thing is that I went through the exact same troubleshooting process. I was going to document my findings, but now I guess I can just share his article ;)

The Endless Quest To Make My Windows PC Stay Asleep Overnight

Ref:
Windows 10 wakes randomly from hibernate - Microsoft Community
Update Orchestrator Reboot - Microsoft Community
windows - Disable UpdateOrchestrator Reboot task - Super User
Administrator account not allowed to disable UpdateOrchestrator Reboot - Microsoft Community
How to permanently stop Windows 10 reboots after installing updates

Sunday, February 4, 2018

Win10: unremoveable language keyboard

I was poking around the language settings, and somehow I ended up with 2 language keyboards which I was unable to remove through the UI. I ended up editing registry in order to fix it.

  1. open regedit
  2. navigate to HKEY_CURRENT_USER\Keyboard Layout\Preload
  3. 0x00000409 corresponds to English (United States). Rename it's key name to 1 if necessary, and then remove all other extra keys
  4. logout
For a list of keyboard layout values, see
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout\DosKeybCodes

Saturday, February 3, 2018

Win10: remove optional language feature

  1. Navigate to Windows Settings > Apps & features > Manage optional features
  2. Locate the optional feature you want to uninstall, select Manage
  3. It will switch to the Region & language screen which is quite confusing. Under the language list, remove the undesired language
  4. Now navigate back to Manage optional features, the previously selected feature should be removed
Ref:
Cannot remove languages from Optional Features - Microsoft Community

Wednesday, January 24, 2018

Win10: Profile picture location

If you ever wonder where the profile picture is stored on Windows 10, it is located at:
C:\Users\your_username\AppData\Roaming\Microsoft\Windows\AccountPictures

You can simply navigate to the following path:
%appdata%\Microsoft\Windows\AccountPictures

Thursday, November 16, 2017

Firefox: Reset certificate database

I was testing a secure server connection over SSL with a self-signed certificate. Typically, Firefox would show a warning about the self-sign certificate along with an "Advanced" option which allows us to add an exception for the site. However, recently I ran into an error code: SEC_ERROR_REUSED_ISSUER_AND_SERIAL, which doesn't have the option to grant the exception. I tried going into the Certificate Manager and remove the previous exceptions but the error persisted.



I was able to resolve this by deleting the cert8.db which basically reset the certificate database. The cert8.db is located in your Firefox profile:
C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile_name>