Solve- Change Virtual Machine ( Virtual Box ) Android Machine Full Screen Resolution Change

1- Open your Virtual Android Machine and select debug mode Option and enter.

 2- Wait until the process will complete then press enter.

 3- In command prompt Run this 3 commands step by step

• mkdir /boot                                           ( create Boot folder )
• mount /dev/sda1 /boot                          ( Mount your disk with boot folder )
• vi /boot/grub/menu.lst                           ( VI for edit your grub )

 4- Press "i" (for edit) and go to the first line begins with kernel /android, and add vga=ask after SRB=/android-... ( Look the image )  ↴

 

5- After edit press "ESC" (Exit editing) then press shift+zz (save and exit).
6- In the command prompt run this commands.

• umount /boot                             
• rmdir /boot                                 ( Remove your directory )
• reboot -f                                      ( Rebooting )

7- After Reboot close your machine for set your resolution in vga list.
8- Check your main machine resolution. In my case my machine resolution is 1366x768x32.Open Terminal (Linux) or Command prompt (Windows) and run this command.

•   VBoxManager setextradata "Android-9" "CustomVideoMode1" "1366x768x32"

( Replace Android-9 with your android machine name and replace resolution 1366x768x32 with your Main machine Resolution.)

9- Now start your Android machine.

 10- Press enter for selection your resolution list.

 11- Check your resolution in this list and type the number of your resolution and press enter.

 

After this booting process you will get your Full Screen Resolution Android Virtual Machine.

Hack The Box Connect your 1st Machine Setup your HTB Machine for Testing

Create Lab

1- Create Virtual Box Machine or Virtual Machine with Kali Linux
2- Install OpenVpn by this command (I have already installed).

 sudo apt-get install openvpn

Now How to Connect Machine of Hack The Box.

1- Login to Hack The Box.

https://www.hackthebox.eu/login

2-  Go to  Access and read Lab Access Details.

 3- Also Check current status of your Server.

4- Download the Connection Pack file.

5- Downloaded file Extension is ".OVPN". Now connect server using this file. Run this command on terminal.
sudo openvpn download_file.ovpn

replace file with your downloaded file and run the command. After running you got the message after success Completed. 
Do not close this Terminal after completed. 

6- Also check status on your site.

Your server connection status is UP.

7- Now select the machine of Hack The Box. Select All option below in Machines for showing all Machines.

Right side you have options for Filters. Now filter which machine you want to connect.

After filter select any machine and open by clicking on name of machine.
you got this window.

Now you have a Name of your machine and IP.
8- Ping this ip on terminal by this command.
ping 10.10.10.181
if your ip pinging that mean you are success full established your connection with your Hack The Box testing machine.


Now Enjoy Testing your Hack The Box Machine.

Hack The Box Sign-UP INVITE CODE 2020 Login Step by step Process Make Invite Code for HTB

1- open this site Link

https://www.hackthebox.eu/invite

2- Right Click on page and go select "View page source" from menu.

3- Select Console Tab.

4- In the Bottom of the console type makeInviteCode() and Enter.

5- After enter you get the code below in data. Copy the code its inscripted code.

6- Also below provide enctype "BASH64"option which provide you your decryption of this code.

7- Go to this site for decode this code, Past your code on this site and select Encode.
https://www.base64decode.org/

 8- In this output decode data you have a path "/api/invite/generate"
  Copy this path it's help to create your full url for generate key look below.

Open CMD (Window) | Terminal (Linux) and run this command.

curl -XPOST https://www.hackthebox.eu/api/invite/generate

9- After run this command you have output with Success Code. This is your final Encoded Key. Copy this code, and again decode this by same bash64 link.
https://www.base64decode.org/

 10- Now you have your fresh key for create New user Account for Hack The Box. Copy this Decode Key and past on your Hack The Box invite code input.
https://www.hackthebox.eu/invite

                    Now go for Sign-UP Your New Account.

Dual Boot (Linux,Windows10) Boot option menu missing Linux entry , Linux kernel Headers Missing , Missing VMLINUZ file, Rescue a Non-Booting GRUB-2 Operating System Missing,Crash,Corrupt

Errors :-

1- Dual Boot (Linux,Windows10) Boot option menu missing Linux entry.
2- If  Operating System missing or corrupt or crash
3- Showing Black screen with command prompt grub:
4- Missing VMLINUZ file form boot folder.
5- Missing Linux Kernel Headers.
6- How to Rescue a Non-Booting GRUB-2.

COMMON REASON:- Because Linux Kernel Headers files are missing.
  

Solutions :-

 1- Boot with live Linux OS CD/USB.
 2- Select Try Ubuntu without installing.

 3- Open terminal after booting complected run this commands.
    sudo fdisk -l  also use  sudo lsblk -l    (Both command provide disk detail. For checking your Linux disk and EFI partition detail list)
 After find your installed Linux partition and EFI partition run next command for mounting your installed disk and partition for repairing your grub.
    sudo mount /dev/sda4 /mnt      (Here sda4 is my Linux partition)
    sudo mount --bind /dev/pts /mnt/dev/pts
    sudo mount --bind /proc /mnt/proc
    sudo mount --bind /sys /mnt/sys
    sudo chroot /mnt
4- After success this full process without any error run this command
    apt-get install --reinstall linux-image-generic
(This process require some time with internet connection.)
5- Reboot the system and remove the CD/USB
6- Select 'C' for command line.

 7- This type of window (command-line) open on your screen.

 Run this command step by step on command prompt.
    ls                            (For know about your drive and partition)
    ls (hd0,gpt4)           (hd0 is my hard disk and gpt4 is my Linux partition after run ls)
    set root=(hd0,gpt4)
    linux /boot/vmlinuz-5.4.0-33-generic root=/dev/sda4           
    (use tab for your vmlinuz version which found in /boot directory replace with your version.)
     initrd /boot/initrd.img-5.4.0-33--generic          
    (use tab for your initrd version which found in /boot directory replace with your version.)
     boot
8- Finished. After boot command your computer will boot with Linux. after booting and login please update your grub with this command.
    sudo update-grub