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A Little Primer on Bootloaders, Encryption, and Signing

A tweet from #AndroidPolice on Android booloaders and the security mechanism around it came to me through #cyanogen today.  While it’s not meant to be comprehensive, I think it does help point developers and modders in the right direction to understanding come fundamental building blocks in information security.  The fact that these security circumvention techniques float about on the Net goes to show that although the underlying encryption schemes and ciphers remain intact, hackers have consistently managed to find attack vectors that “side step” these measures, hence the term “circumvention”.  It’s a proverbial game of cat and mouse perhaps calculated to cost-effectively block a majority of users while appeasing to script kiddies and modders alike.  Link to the post on Android Police here.

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Vibo A688 Runing CM7

Prologue-

I recently arrived in Taiwan, where my Sprint EVO 4G/HTC Supersonic became more of a Wifi-only device. While Asia Pacific Telecom offers CDMA 1X here in Taipei, EvDO with 3G speed is sorely lacking, let alone WiMax implementation.  Besides, the rest of my family members here are on Chung Hwa Telecom, which happens to be the largest network here by virtue of its heritage as a state-run monopoly until recently, so I find it more economically sound to stick with Chung Hwa.  The problem is, however, I need a GSM phone.

Prior to the explosion of data-minded smartphones flooding the market, I had a couple of free or near free GSM phones subsidized by US carriers like PacBell (which then became Cingular before morphing back to Ma Bell – AT&T) and T-Mobile.  It was pretty sweet, get a new phone for free or even get money back after rebate for jumping over to T-Mobile and be on the hook for only a year.  These days, you would most likely need to sign up with a two-year contract.  Now that I have switched to the CDMA camp with Sprint, the freedom of swapping out my home SIM with a local one is no longer an option.

Enter Vibo A688 (Commtiva Z71 Varient)-

A friend here had a Vibo A688 Android device on the Vibo GSM network.  At a first glance, it looked a lot like T-Mobile’s myTouch, but was made by Foxconn instead of HTC.  My friend had it for more than a year, and said she never liked it because it was not very responsive.  She had dropped the device, and now it has a cracked screen, but still functional, for the most part.

It came prettty crippled with Android 1.5, so I looked around on the web for ways to root it and perhaps load some updated ROM.  Vibo’s support website has a link for an updated 2.1 firmware, which underclocked the device from 600MHz to 480MHz max freq on purpose.  My guess is for power consumption’s sake.  I tried it for a few minutes, but didn’t like it much, so I looked to the good folks at CyanogenMod.

Time to Tinker-

I found z4root on xda-developers to be exceedingly simple to root this phone with pretty much a one-touch root process.  Of course there are inherent dangers in rooting your phone, so the usual disclaimer applies, especially with a one-click root process where you, the script kiddie, may not understand what it is that you’re doing to your phone.  After the A688 is rooted and a custom bootloader installed, it was time to load a custom recovery (I used koush’s clockworkmod recovery).  It wasn’t immediately obvious to me which device this A688 falls under, but a trip to Google came back with the hint of Commtiva Z71 Varient.  I loaded CM 7.0.3.1 and a custom boot splash that I cooked up, and all was done within 3 hours of getting my hands on this poor device.

I have since flashed back and forth between Vibo’s 2.1 ROM and CM7, and find that user experience to be superior on CM7 with ondemand governor and  600MHz/122MHz max/min freq.  Because of the dismal amount of available RAM, I have had to do away with many apps I had grown accustomed to on the EVO 4G, or the system would start killing processes when switching among multiple apps.   I didn’t try to tinker with CMPart’s setting to lock home in momory or decrease VM heap size, so your mileage may vary.

*Update May 23, 2011 15:10 GMT*
I enabled Compcache pursuant to this post, and have found marked improvement in available memory without noticeable performance hit.  Granted that I’ve only just turned it on an hour ago, but the difference seems obvious for my use case.  I’m using 18% of the RAM as Compcache, and find a corresponding increase in available RAM.  I expect more drain on the battery, but I’ll report back once I have more time playing with this setting, so stay tuned.

A few gripes-

So far, I have had problems with the SD card being unmounted by itself at random times.  I’m not sure if it’s a defective card or something else.  Coming from the EVO 4G with 1GHz snapdragon, A688′s MSM7227 (also by Qualcomm) definitely is quite a bit slower.  It is especially annoying  when using Google Maps to navigate around Taipei’s crisscrossing streets.  I’ve missed innumerable turns while the phone struggles to keep up with my location.

Anyway, that’s all for now.  I’ll try to post some screenshots and updated links in a few days.

Screenshoots-

Peter

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High WSJ: Court to Hear Microsoft Appeal in Patent Case

High Court to Hear Microsoft Appeal in Patent Case

Read more: http://online.wsj.com/article/SB10001424052748704584804575644633158363078.html#ixzz16kA350cO

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[ROM] Baked Snack 1.8 for HTC EVO 4G (Supersonic)

Android Froyo based ROM for the HTC EVO 4G by Hero_Over.

Click to continue reading “[ROM] Baked Snack 1.8 for HTC EVO 4G (Supersonic)”

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Tan Le: A headset that reads your brainwaves

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Android Phone Recorder Problem

Note:  I don’t have time to complete this posting right now, so it’s in a draft format.  I just wanted to briefly document my findings before I forget.  Back to studying for the Patent Bar…

I finally pony up the Benjamins and got myself an Android handset, wait for it – the Sprint HTC EVO 4G!

You may not share my enthusiasm, but finally ditching my HTC Mogul (running WinMo 6.1) and moving into an even more open platform opens up a lot of possibilities for me.  I’ve always been more comfortable developing on the *nix realm, and although I don’t have anything against the iPhone, Apple’s tight control on the iPhone OS just doesn’t sound that appealing to me.  At this point in the mobile platform ecosystem, iPhone enjoys a  almost 4-to-1 margin in the number of developers probably due to its two year head start in reaching the mainstream market, but the fact that Google opens up the entire Android platform, allowing me to develop apps that interface the hardware in a low-level way is much more appealing.  I hope for a day when the mobile platform mimics the general purpose computers that makes it possible to run almost any OS on the same hardware.

A bunch of people have been having problem building a true phone recorder on the Android.   Almost all smartphones these days come with an application processor (AP) and a baseband processor (BP).  The BP is responsible for handling the radio, and voice encoding -decoding, among other related tasks.  While the AP is used to run the OS and applications.  The fact that despite having an API that supports recording voice call (both uplink and downlink), none have been able to successfully implement the feature suggests to me that there’s more than meet the eye.  Upon further digging through the Android platform source and documentation, I found an interesting project within the platform that seems to be responsible for implementing what I want…, the Radio Interface Layer (RIL).

More to come…

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Android 2.2 (Froyo) To Come with Tethering and Wifi Hotspot

I have been USB-tethering with my Sprint HTC Mogul for more than two years, connecting my Ubuntu 8.04~10.04 and Win XP~7 laptops/netbook to Sprint’s usually-speedy-enough 3G data network. While my Mogul still works fine as a phone, email client, light browsing, an GPS navigation with Tomtom 7 and Google Map, I am really getting tired of Windows Mobile 6.1.

I am a fan of building custom Linux kernels for the x84 architecture and having root access to an OS, so the ability to do (close to) the same on a ultra-portable embedded device with an ARM architecture with an Android OS appeals to me.

The hardware I want is something like the HTC Evo (4G) or the HTC Desire/Incredible. While the Android 2.1 that comes with them pretty much does what I need, and I think I can always tinker around to get USB or Wifi tethering, the rumor that Android 2.2 will come with that ability built-in gets me fired up.  Sprint says they’ll be charging an additional $29.99/month for Wifi hotspot on the Evo, so it remains to be seen if a carrier will disable the new built-in Wifi hotspot capability so they can charge more.

If history is an indication of what’s to come, I may have a reason to be optimistic.

Back in October 2007 when I got my Mogul, rumors were that there was a GPS module built-in, but Sprint had disabled it in the ROM.  A few months later, Sprint released a new ROM with that GPS module enabled, even though they continue to provide their proprietary Sprint Navigation at a monthly fee.  I hope they somehow decide to allow the native Wifi hotspot, but I’m not holding my breath for it.

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ARM, Globalfoundries outline 28-nanometer plans

“The companies revealed the details Monday at Mobile World Congress in Barcelona. Their system-on-a-chip platform is based on ARM’s Cortex-A9 processor and Globalfoundries’ 28-nanometer manufacturing process. The platform will be used in smartphones, tablets, and smartbooks.”

Full story at News.com.

So it looks like we will have devices that consume less power purely on a per-clock-cycle basis.  I’m guessing the new process won’t trickle down to actual commercial mobile implementation until at least 2013.

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Microsoft urges laws to boost trust in the cloud

From CNET:

In a speech Wednesday, Microsoft general counsel and senior vice president Brad Smith called on government and business to shore up confidence in cloud computing by tackling issues of privacy and security–two major concerns that have been voiced about the cloud.

Full article.

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Waiting For A Nexus One Worldphone

So Google finally announced its 3G phone for HSPDA back on Jan 5, 2010. Unfortunately, for those of us in the US, the GSM camp does not have a wide enough of 3G data coverage that folks over in Asia and Europe enjoy. I was pretty excited when Google said they would release a version of Nexus One that works on the Verizon network in the Spring of 2010. After all, my contract with Sprint doesn’t expire until May.

Since the GSM Nexus One packs the Qualcomm Snapdragon QSD8250, which according to Qualcomm’s specs only works on the GSM network, I am guessing that the CDMA version would be screaming with Qualcomm’s QSD8650.  According to specs from Qualcomm, the QSD8650 is compatible with both GSM/HSDPA and CDMA/EV-DO, making it a true 3G worldphone (unless you still need iDEN, which I think only Japan and Korea might still be deploying, and Sprint is phasing it out after acquiring it from Nextel).  This would be a very nice phone unlocked, allowing a world traveler to utilize local networks at cheaper rates.

According to a press release from Qualcomm in summer 2009 (will dig up the press release later…), they have managed to clocked QSD8650 at 1.3 GHz, a third faster than QSD8250′s 1GHz.  Since both chipsets are fabricated using the 45nm process, power-saving from lower voltage should be out of the question.  It would be interesting to see how, if at all, Qualcomm can still manage to maintain a comparable running time without sticking a bigger and heavier battery on the back of the phone.

In a way, I am glad that my contract with Sprint isn’t up yet, so I don’t have to rely purely on my (limited) restraint to compulsively buy a GSM-only Nexus One now.

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