Hotspot

Hot Spot 2.0 (HS 2.0), also called Wi-Fi Certified Passpoint, is a new standard (IEEE 802.11u) for public-access Wi-Fi that enables seamless roaming among WiFi networks and between WiFi and cellular networks.

How does it all work?
1. The client sends an ANQP query to the AP.
2. In ANQP response, client gets list of Online Signup (OSU) providers that are reachable from this hotspot.
3. The list typically is displayed at client as an icon and operator friendly name.
5. Once the user selects an OSU provider from the list, client connects to the OSU WLAN (Open or OSEN).
6. Client then makes an HTTPS connection to the OSU server URI to finish registration/purchase.
7. On success full registration, security credentials are pushed to client.
8. Now client disassociates from the OSU WLAN.
9. And connects to the HS2.0 WLAN using the standard ANQP mechanism.

GAS => Generic Advertisement Service
ANQP => Access Network Query Protocol
Client uses GAS query (with ANQP IEs) to get ANQP Capability list from AP. This will enable client to identify AP’s network and service provider.

Software Hotspots
Wi-Fi adapters in computers could operate as hotspots.
1. Windows 7 have built in support for hotspot.
2. Third-party software vendors, offer applications to allow users to operate their own Hotspot.

How to Enable a Virtual WiFi in Windows

make sure "Microsoft Virtual WiFi Miniport Adaptor" is created.

http://www.wikihow.com/Enable-a-Virtual-WiFi-in-Windows

# netsh wlan set hostednetwork mode=allow ssid="Homewifi" key="passphrase" keyUsage=persistent

# netsh wlan start hostednetwork

Reference:
http://en.wikipedia.org/wiki/Hotspot_%28Wi-Fi%29
http://whatis.techtarget.com/definition/Hot-Spot-20-HS-20
http://www.theruckusroom.net/2014/10/hotspots-get-hotter-with-release-2-of-hotspot-20.html
http://www.arubanetworks.com/techdocs/ArubaOS_64_Web_Help/Content/ArubaFrameStyles/hotspot/predepoyment_overview.htm

Cyanogen on Nexus 7 (2012)

CyanogenMod is an aftermarket firmware for a number of cell phones based on the open-source Android operating system. It offers features not found in the official Android based firmwares of vendors.

Cyanogen commercially develops operating systems pre-installed on some devices (OnePlus One, YU Yureka, YU Yuphoria, Andromax Q, Lenovo ZUK Z1, Wileyfox Swift, Wileyfox Storm) based upon the CyanogenMod source code.
Initially distinguished with the suffix -S (CyanogenMod 11S), with version 12 Cyanogen rebranded the custom offering as Cyanogen OS.

Unlock the bootloader

# adb reboot bootloader
# fastboot oem unlock

Download latest CM recovery image from cm-grouper.

Installing recovery using fastboot

# adb reboot bootloader
# fastboot erase recovery
# fastboot flash recovery cm-12.1-20150901-SNAPSHOT-YOG4PAO237-grouper-recovery.img
# fastboot reboot-bootloader

Installing CyanogenMod from recovery

http://download.cyanogenmod.org/?type=snapshot&device=grouper
- Enter "Recovery mode""
-- Wipe data/factory reset
-- Wipe cache partition
-- Apply update
--- Choose from internal storage
---- 0
---- "cm-12.1-20150901-SNAPSHOT-YOG4PAO237-grouper.zip"
# fastboot reboot

Open Gapps is the best place for downloading Google apps suit for custom ROMs. Open Gapps packs common Google apps suit including Google Play Store app.
Download latest Open Gapps package from ogapps-nano

Installing Open Gapps 
# adb push open_gapps-arm-5.1-micro-20151002.zip /data/media/0/
# adb push open_gapps-arm-5.1-micro-20151002.zip /sdcard/
Enter "Recovery mode"
- Apply update
-- Choose from internal storage
--- 0
--- "open_gapps-arm-5.1-micro-20151002.zip"
# fastboot reboot

Lock the bootloader

# adb reboot bootloader
# fastboot oem lock

2. Installing from factory image
Download latest Google Nexus image from Nexus 7(2012).

Flashing Nexus image from Google

# adb reboot bootloader
# fastboot oem unlock
# flash-all
# fastboot oem lock

3. Installing from AOSP image
1. Recovery image TWRP 3.0.0.0 from here.
2. Marshmallow 6.0.1_r13 OTA-Package from here
3. Gapps for 6.0 from here.

Flashing Marshmallow image

# adb reboot bootloader
# fastboot oem unlock
#
#
# fastboot flash recovery twrp-3.0.0-0-grouper.img
# fastboot reboot
#
# press holding 'Volume (up)', 'Volume (down)' and 'Power' buttons.
# Enter recovery mode
# or
# adb reboot bootloader
#
(RECOVERY)# adb push aosp_grouper-ota-eng-20160203.ds.zip /sdcard/
(RECOVERY)# adb push benzo-gapps-M-20151011-signed-chroma-r3.zip /sdcard/
#
(RECOVERY)# From Install menu select AOSP OTA image and flash
(RECOVERY)# Reboot System
#
(RECOVERY)# From Install menu select GAPPS image and flash
(RECOVERY)# Reboot System
#
# fastboot oem lock

Reference:
https://en.wikipedia.org/wiki/CyanogenMod
https://wiki.cyanogenmod.org/w/Install_CM_for_grouper
http://download.cyanogenmod.org/?type=snapshot&device=grouper
http://techtrickz.com/download/open-gapps-project-best-place-for-downloading-latest-and-correct-google-apps/
https://developers.google.com/android/nexus/images
http://forum.xda-developers.com/nexus-7/development
http://forum.xda-developers.com/nexus-7/development/android-6-aosp-grouper-t3268172