asoa's blog

Why do I have to see this every time when I have to login? I have paid them for 2 months in advance when I applied for their connection. It isn’t two months yet and I am seeing this ever since I got the connection.

Why can’t they just display this message to those customers who’s payments are due rather than displaying it to everybody? Who knows somebody with a weak heart could get a heart attack seeing this reminder.

Wireless LANs operating on the same channel or even in the same spectrum can interfere with each other. This interference, called co-channel interference, is caused by frequency reuse and is most common in 802.11b/g networks. Since the 802.11b/g standard allows for only three non-overlapping channels, frequencies must be reused within the same area when more than three APs are required. Co-channel interference is something that degrades your WLAN throughput and can hurt your WLAN’s performance.

You can also get co-channel interference between overlapping channels in the 802.11b/g spectrum. For example Channel 6 operates between 2426 MHz and 2448 MHz, and Channel 7 uses 2431 MHz to 2453 MHz. This means 17 MHz is used by both channels. Because only one device can transmit on any given frequency, they are effectively sharing 77 percent of their bandwidth, which degrades WLAN performance.

Even though channels 1 through 6 are marketed as non-overlapping for Channel 11, an RF phenomenon called side lobes (basically, power leakage into unintended frequencies) causes them to give off minimal interference. But this is eliminated at greater distances.

Although many devices can interfere with WLANs, adjacent WLANs are the most overlooked culprit. The frequency in which WLAN devices operate is valuable so carefully plan and deploy your WLANs to avoid potential interference.

The credit for the pictures in the article goes to “Protection Ripple in 802.11 WLANs” by Devin Akin, CTO – CWNP.

My first article explains the steps to activate/jailbreak and unlock a new iPhone to firmware 1.1.1. This article instead explains the steps to revirginize an iPhone which has been unlocked with AnySim 1.0 and most other unlocking tools apart from Iphonesimfree and AnySim 1.1

To revirginize.

01. Download the BSD subsytem.
02. Donwload the tools (virginizer_pack) to flash the baseband.
03. Connect the iPhone to WiFi so that you can access it over WiFi
04. Copy the BSD Subsytem and virginizer_pack to the iPhone using SCP
05. SSH to iPhone
06. Backup the seczone
07. Run the virginizing tools to flash baseband to the original 03.14.08

Now I have a virgin iPhone.

08. Using iTunes update the firmware to 1.1.1
09. Activate iPhone using Independence.
10. Jailbreak iPhone (this would be done automatically in step 09).
11. Install SSH on iPhone via Independence.

Now to unlock the iPhone so that it works on my non AT&T sim.

12. Download AnySim 1.1
13. Copy AnySim 1.1 to the iPhone using Independence
14. Run AnySim 1.1 and follow instructions.

Hooray, now I have revirginized an iPhone which was unlocked using AnySim 1.0 earlier and activated, jailbreaked and unlocked it with firmware 1.1.1 which works on my non AT&T sim.

Unlocking iPhone is just a snap if you are familiar with the unix commands and use Mac OS X.

My first try was with a total new iPhone (firmware 1.1.1). Find below the steps I used to activate, jailbreak and unlock the iPhone with 1.1.1 update.

01. Used my non AT&T sim in the phone.
02. Use Independence to take the iPhone to Recovery mode.
03. Download the firmware 1.0.2 from Apple site.
04. Restore the 1.0.2 firmware to the iPhone using iTunes.
05. Wait for iTunes to finish, once done Quit iTunes.
06. Launch Independence again to get the iPhone out of recovery mode.

Now I have the iPhone in firmware 1.0.2

Now to upgrade it back to 1.1.1 so that I can activate/jailbreak the iPhone.

(Please note that if you have used anySIM 1.0 or other older free SIM unlocking solutions (anything except for anySIM 1.1. and iPhoneSimFree) to SIM unlock your phone, and you upgrade to 1.1.1, it will wipe out the SIM unlock and render the phone and text message part of your phone inoperable. Everything else will work though).

07. Launch Independence and activate the iPhone.
08. Use Independence to Jailbreak the iPhone.
09. Install SSH on iPhone via Independence.
10. Connect the iPhone to WiFi so that I can access iPhone over WiFi.
11. Do a Pre 1.1.1 upgrade using Independence.
12. Using iTunes update the firmware to 1.1.1
13. Activate iPhone using Independence.
14. Jailbreak iPhone (this would be done automatically in step 13).
15. Install SSH on iPhone via Independence.

Now to unlock the iPhone so that it works on my non AT&T sim.

16. Download AnySim 1.1
17. Copy AnySim 1.1 to the iPhone using Independence
18. Run AnySim 1.1 and follow instructions.

Hooray, now I have an activated, jailbreaked and unlocked iPhone with firmware 1.1.1 which works on my non AT&T sim.