Category Archives: Cell Phones

Huawei P8 (GRA-L09) modding

This post about “modding” of a Huawei P8 aims to summarize most of the standard procedures you need when you want to modify the device software (also called “firmware”), because you are a developer or want to be more flexible in how you use your device.

Normally, in order to gain this knowledge, you have to read a lot of “geeky” posts on sites like xda developers, which is very time consuming, and sometimes even leads to complete failure (you end up “bricking” your device), because many people there don’t bother to post clear and comprehensive instructions, but simply assume people have some pre-knowledge and know how to do things.

I don’t yet consider this post “finalized” yet (it needs some “polishing”), but I would like to make it available already now to make sure it won’t be forgotten… 😉

Fastboot Mode

“Fastboot” mode is a special mode your device can be put into in order to perform certain maintenance operations, such as (un-) locking your boot loader, flashing partition images, etc. The tool you use on your PC or Mac to communicate with the phone while it is in “fastboot” mode is also called fastboot. It is part of the Android platform tools which you can download here directly from Google.

Continue reading Huawei P8 (GRA-L09) modding

Sony Xperia X Compact Modding

I decided to write this post since I couldn’t find any single page that lists all the “secrets” you need to know when modding your Sony Xperia X Compact (XC) codenamed “Kugo” in a concise manner and in a single place. And after half a year when I last tinkered with my XC, I had forgotten about all the details again, so I had to research them again anyway…

I give credit to the following XDA people (but not limited to them, I apologize to those who I might have forgotten):

General Approach

The general approach when modding your phone is the following:

  1. Flash custom recovery
  2. Backup current installation/data
  3. (Optionally: flash latest stock firmware)
  4. (Optionally: flash custom recovery that works with your new stock firmware)
  5. Root
  6. Flash other mods or use “root” apps

Custom Recovery

Fastboot Mode

First let’s explain what “fastboot mode” is: Fastboot is both a tool and a protocol for writing data directly to your phone’s flash memory. In practical use, it is used to flash images such as recoveries, bootloaders, and kernels to your Android device.

The “fastboot” tool (as well as “adb” which is also needed when tinkering with your Android smart phone) is part of the Android “platform tools,” which you can download directly from Google (roughly 4M only).

To bring your phone into fastboot mode, perform the following steps:

  1. Switch the phone off.
  2. Hold “Volume up” and connect your phone to the USB port of your PC. The notification LED should first light up in red, then blue, and provided you have correctly installed drivers, you will be able to use fastboot commands.
    Note that the screen will remain black. You can check whether you are in fastboot mode with the following command:

    $ fastboot devices
    BH901XXXXX    fastboot

    If you see output similar to the above, you have successfully put your phone in fastboot mode.

Continue reading Sony Xperia X Compact Modding

My VerizonWireless prepay experience

We just returned from a one month vacation trip to Florida. In order to be able to use the internet when on the go, and also to be able to make and receive phone calls we decided to use a prepay card from VerizonWireless (VZW), as they seem to have the best 4G (LTE) coverage. The SIM is normally $45 for a month, including unlimited texts and calls and 1 GB of data, but we got it from Walmart for about $37, plus we received a free one-time bonus of 1 GB data when we activated the SIM via phone.

Our customer experience was pretty bad, and I want to share with you what kind of problems we had so that you can avoid those if possible.

The phone I intended to use was an iPhone 6 Plus. This cell phone is among the cell phones that have the most LTE bands available in the world, and I explicitly checked to make sure that VZW’s bands are covered. But when I tried to use the phone it couldn’t attach to the network. I got in touch with VZW, and it turned out that they only let phones use their network (with their own VZW prepay SIMs, that is!) that have been sold by or for VZW. But after talking to them for a while and letting them know about my disappointment (because in Europe this doesn’t seem to be common) they agreed to make an exception and have my iPhone authorized to use the network.

Even after four days (they said it should take 48 hours max), more than 3.5 hours talking to or chatting with their support, and even changing the SIM in a nearby VZW store, my iPhone still didn’t work, so I looked into other options. It turned out that you can buy simply 4G cell phones here real dirt cheap, so I bought a Motorola Moto E (2nd Gen) for less than $50. This phone immediately worked with the SIM I had.

I logged onto their MyVerizon prepay Desktop Home page to check and update some settings. This portal was another really bad experience, something which you really cannot ask your customers to use. The issues I encountered were the following:

  • After I had entered my address here in Florida (we lived in the house of relatives), there was trailing characters in the street address which I didn’t enter, and which I could not remove by any means.
  • Furthermore I couldn’t change my device from the original iPhone 6 Plus to the new Motorola Moto E — all changes (including IMEI which was verified to be “valid” and “known” to VZW) seemed to the accepted, and change of device was confirmed, but when I went into the main menu and back to “Device” the iPhone was still listed.
  • In addition I couldn’t change my Voice Mail PIN, probably the reason why voice mail was not available for my SIM during the whole month of our stay.

As an alternative to the bad web portal I installed the “My Verizon Mobile” Android app, but that was disappointing, too. There was absolutely no way to tell the app not to ask for the password again — a bad thing as I normally use “strong” passwords which I cannot easily remember, so how to use the app when on the go?! More issues encountered were

  • “Usage” details permanently give me “An error occurred while processing your request;”
  • in “My Features” I couldn’t activate the “Block Premium Messaging” option (even though changing the switch produced a confirmation that said the change was successful); every time I return to this menu item the setting is back to allow premium messaging;
  • in “Settings” > “Contact Info” I couldn’t make any changes, as the app declared my email address invalid (as it contains a “+” in the so-called “local-part,” which is the part left of the “@”). That was of course nonsense, as RFC-2822 allows such email addresses, I constantly receive mail on such addresses and VZW’s web portal allowed it as “valid;”
  • changing my Voice Mail Password (PIN) was also impossible in the Android app. I always got an error message saying “We are sorry, but we are not able to process your request at this time. Please try again later.”

What I must admit, though, their staff were always very friendly and tried to help — but what can you do if your IT systems let you down?!

The main reason I write this blog post is to let people from Europe know about the limitations they might encounter when trying to use their own phone with a local prepay SIM. But I also want to let VZW know my frustration with their bad self-service tools. This is not how you treat your valuable customers!!!

Aktuelle Smartphones verglichen

KĂŒrzlich stand ich vor der Anschaffung von zwei neuen Mobiltelefonen (im Rahmen von VertragsverlĂ€ngerungen bei Vodafone). Daher habe ich die wichtigsten bei diesem Anbieter erhĂ€ltlichen aktuellen Smartphones verglichen.

Folgende Handys habe ich verglichen (in alfabetischer Reihenfolge):

Apple iPhone 5S, Apple iPhone 6, HTC One (M8), HTC One (M9), HTC One mini 2, LG G3, Huawei P8, Nexus 6, Samsung Galaxy Alpha, Samsung Galaxy S5 16 GB, Samsung Galaxy S5 mini, Samsung Galaxy S6 32 GB, Samsung Galaxy S6 64 GB, Sony Xperia Z3 Compact, Sony Xperia Z3.

Die Kriterien bei meinem Vergleich waren Folgende:

  • Geschwindigkeit der CPU und Anzahl der Kerne
  • GrĂ¶ĂŸe des Arbeitsspeichers (RAM) und des internen Massenspeichers (Flash),
  • BildschirmgrĂ¶ĂŸe und -auflösung,
  • LTE-Geschwindigkeit und Anzahl der LTE-BĂ€nder (wichtig, da ich GeschĂ€ftsreisen auch auf andere Kontinente unternehme),
  • VerfĂŒgbarkeit von VoLTE,
  • Bluetooth/WiFi/WLAN-Versionen,
  • NFC-VerfĂŒgbarkeit,
  • Wechselbarkeit des Akkus durch den Benutzer,
  • Repair Score (wichtig, falls das Handy auch nach Ablauf der GewĂ€hrleistung weiter benutzt werden soll!),
  • Akku-KapazitĂ€t,
  • drahtlose Akku-LadefĂ€higkeit ĂŒber Qi,
  • SIM-Typ und
  • Marktpreis.

Und hier nun der Vergleich in Form eines Excel-Sheets:

Handyvergleich 2015-07-09

War das hilfreich? Dann wĂŒrde ich mich ĂŒber entsprechende Kommentare hier in meinem Blog sehr freuen.

Update 2015-07-09: Excel-Sheet upgedated. Huawei P8 hat deutlich mehr LTE-BĂ€nder als hier angegeben — insgesamt nĂ€mlich 16 beim Modell GRA_L09 laut Huawei selbst. Damit scheint es das Mobiltelefon mit den meisten LTE-BĂ€ndern zu sein.

How to install Android 5.0.1 on HTC Desire S

By chance I came across a thread on xda-developers that explains how to install CyanogenMod 12 (cm12) on an HTC Desire S (codename “Saga”). Being a newbie in “hacking” and rooting Android phones I had to read, investigate, and try a lot.

To spare you this effort I’m trying to summarize the steps required below:

  1. Unlock bootloader: To be able to flash a custom bootloader you first need to unlock the bootloader, which is easy since HTC makes this officially available via their web site.
  2. Flash recovery image: I used Team Win Recovery Project 2.8 (or short TWRP 2.8) which I downloaded from a link on this site.
  3. Flash cm12 and Google Apps: Download the latest cm12 image (on 2014-12-05 it was from this page. Download Google Apps from this page. Put both ZIP files on the micro-SD card.
  4. Reboot to your recovery image by keeping “volume down” key depressed and then switching on the phone. Keep volume key depressed until TWRP splash screen appears. Perform a factory reset. Flash the two ZIP files, add cm12 first, then add Google Apps.
  5. Extract boot.img from and flash that with fastboot. Flash it using these instructions.
  6. Reboot your phone. CyanogenMod splash screen should appear after a while. Your first boot will probably take very long (I think for me it was about 15-20 min). Be patient!

After carefully following all the above instructions I now have the following on my HTC Desire S:

  • Boot rom HBOOT-2.02.0002 in mode S-ON
  • Radio/modem/baseband firmware RADIO-3831.19.00.110 (
  • TWRP v2.8.0.0
  • Android 5.0.1 in the CyanogenMod flavor, version 12-20141204-UNOFFICIAL-saga. Kernel version is 3.0.101.
  • Google Apps referred to from this page.

Thanks to everyone on xda-developers for their excellent work and support!

You might encounter the following issues which can be fixed as specified:

  • Touch screen not working properly: You have kind of a “mouse pointer” which you can drag around with your finger on the screen. To “click” something you have to double-tap on the mouse pointer. Fixing this can be accomplished by following this procedure.
  • The home softkey doesn’t work. Fix it by following these steps.

I had success with the following (not meant to be complete, just a couple of things which I consider important or surprising):

  • Sending audio to my Plantronics Blackwire C720 Bluetooth headset works properly, using Google Play Music. This was obviously using the “Media Audio” Bluetooth profile.
  • Skype via the above headset works perfectly well. Sound quality is crystal-clear.
  • Hand-over of a voice call to the above Bluetooth handset and back works perfectly well — maybe even better than on my S4… 🙂
  • Paired my Samsung Galaxy S4 with the HTC Desire S. Successfully sent a contact as VCF file from the S4 to the Desire S. But then process crashed.
  • Connect phone to Windows 7 via USB, using MTP protocol. Write speeds to micro-SD card seemed normal.

The following limitations still exist (or at least these are the ones I noticed so far):

  • Phone is somehow regarded as a tablet by the Android OS.
  • Front camera not working. I thought I had seen it working once, but maybe I’m confused. Anyway, as of now the front camera seems not to be detected/functioning. The back camera is working well with the camera app from the minimal Google Apps package as well as from the official Google Camera you can download from Google Play. Skype and Google Hangouts also work well, apart from the front cam.
  • I replaced some of the apps in the apps dock with apps I installed from Google Play. Some of these apps will disappear after a reboot. When I noticed this and wanted to put them back by opening the apps drawer I observed that Android was currently populating/updating the apps drawer with some still missing apps. But even after it had finished showing all installed apps in the app drawer the apps dock was still missing some apps. So I dragged them back from the drawer onto the dock. Again, after a reboot they will be gone again.
  • Speed of cellular data connections seems slow. Unfortunately I couldn’t verify whether the cellular network settings are ok, since every time I tried to enter one of the corresponding  Settings menu item the process would crash (with the effect that I had to re-enter my SIM PIN and also the screenlock PIN).
    Later I tried it again, and this time it didn’t crash. All the settings were fine, so I wonder whether there is a problem with regards to the modem firmware? (I would like to note that I don’t have a voice SIM in this mobile phone, but just a data-only SIM. Eventually the firmware tries to perform operations that work on voice SIMs and doesn’t properly handle situations where those operations cannot be carried out?!)
  • Update 2014-12-11: Connecting the charger when the phone is powered down will cause it to boot into the TWRP recovery system.
  • Trying to open menu item Wireless & Networks > Cellular networks > Carrier Settings might cause process to stop.
  • Ringtone will be quiet on incoming calls.
  • Microphone will be muted (or not properly amplified) when the first outbound(!) call takes place (in non-speakerphone mode). After you have gone on speakerphone and back, the microphone will then be working.
  • Moving apps to the external SD card is unreliable. Often it doesn’t work without any indication as to why. If you then repeat it again it may actually work.

OpenWRT Quality-of-Service module caveat: speed limit

As I still have “issues” with my DSL line being extremely slow during certain times (especially between 18:30 and 23:00), I wanted to use USB tethering from my OpenWRT router to my Android LTE phone to enjoy the massive speed I have in our area (up to 90 MBit/s downlink and 70 MBit/s uplink, according to the Ookla Speedtest.Net).

So I configured the router according to the OpenWRT wiki. The internet connection did not come up immediately, and I couldn’t find out why, so as a last resort I rebooted the router. After I switched on USB tethering again on my mobile phone (which seems to be required each time you reboot the router since the mobile phone then loses the USB tethering connection), I suddenly had a working Internet connection.

However, for some reason the Internet speeds I was seeing in Ookla’s web browser-based speed test (which is a Flash applet) were very disappointing, around the same speeds I’m used to with my DSL line (14 MBit/s downlink, about 0.8 MBit/s uplink). I thought it might be an issue with USB tethering not working well in my build of OpenWRT (still r39582), so I tried USB tethering with my Mac (using HoRNDIS). I got the full speed I expected. So back to OpenWRT…

Then suddenly I suspected what might be going on: Since I had more or less exactly the same speed as my DSL connection (with the uplink of less 1 MBit/s being dramatically slower than what I should get via LTE) I thought about what could possibly limit the speed. And then I remembered that in the “Quality of Service” (QoS) module I configured the speeds of my DSL line (at the top of the page, in the Download speed (kbit/s) and Upload speed (kbit/s) fields). Could it be that these settings actually limit your speed to these values?!

I disabled QoS, and immediately thereafter I got the full LTE speed I expected.

So, another thing learnt.

I hope this helps people who might be in a similar situation…

iPhone 4 Battery Repair

If you follow my blog you know that my old iPhone 4 suffered from the well-known issue of a swollen battery. I didn’t want to throw it away before checking the actual extent of the damage — maybe it could be repaired with little effort?!

So I spent 15 EUR and ordered a Pentalobe screwdriver and plastic opening tools from iFixIt Europe. Only a few days later I received the tools, and using the instructions they have on their website how to open the iPhone 4 and replace the battery it took me only 5 minutes to find out that there was no damage whatsoever to the inner of the iPhone: It was only the battery itself that was damaged (swollen), and the glass back cover that was glued into a plastic frame had become loose.

Here’s a picture of the old battery:


You can clearly see that the battery was not “flat”, but strongly swollen.

Therefore I decided to order a new battery. This time I ordered from eBay since a new battery could be had from there for only 12 EUR, while iFixIt would have charged me 30 EUR (both incl. shipping).

The actual repair was extremely easy: Just unplug the damaged one (after removing a tiny Philips screw that secured the battery plug), and then insert the new one into the iPhone, plugging in the battery cord into its socket, and secure it with the tiny Philips screw.

I also “repaired” the back cover by firmly pressing the glass plate onto the plastic frame. Luckily the glue was still strong enough to firmly hold the glass.

I then assembled the iPhone again, and plugged the charger in. After a couple of seconds, it started booting, and the charging process started, so the new battery seemed to at least not be D. O. A. 🙂

Since I had read comments on Amazon that obviously some people had received used batteries as replacement parts (some had already around 200 charge cycles!), I decided that I wanted to check my battery stats. There’s a tool in Cydia Store called BatteryInfoLite that will display extensive information about your iPhone’s battery, so I decided to jailbreak my phone (that still had iOS 5.0.1 installed) to get Cydia. I used redsn0w 0.9.13dev4, and within only a couple of minutes my device was jailbroken, and Cydia was installed.

Here’s a screenshot of what BatteryInfoLite displayed about my battery:


 The serial number that was displayed by the tool was identical to the one printed on the battery, which I regard as another indication of reasonable quality. The last 4 digits are obviously an indication of the battery’s design capacity.

I felt happy when the phone was working again. I will now use it as an MP3 player (which it essentially is, after all… ;-))

Don’t neglect your iPhone, or else… :-(

I did not use my iPhone4 for a while (since I have a Samsung Galaxy S4 now, which I like much more), and when I wanted to “revive” it recently as a music player I found that it had burst (no, I didn’t drop it, it was just lying around on my desk):


20130927T100257-IMG_0107Obviously the battery had swollen…

I immediately called the Apple dealer closest to my home and told them about it. They said it’s normal for a battery to burst if the device hasn’t been used for a while. They said I could buy a new iPhone 4 for a “mere” 190 EUR… 🙁

If you Google for this issue you will notice that it’s pretty common, still Apple cares a sh*t about it… I’ve never seen such major battery issues on any mobile phone I’ve owned before — and I had many!!!

Thanks, Apple. This is what you get when you buy from a “premium” manufacturer…

Needless to say that I will never buy an iPhone again…

“Call Forwarding” setup on iPhone – what a stupid user interface design…

I’m using call forwarding a lot on my iPhone — every day after I left the office I forward calls to my voice mail, and next morning I cancel this forwarding. Also, in periods where I’m on-call I forward calls to my fixed line as soon as I arrive home, and I cancel this forwarding when I leave home so that I can be reached on my cell phone again…

Ok, here’s the thing I’m complaining about: When you want to enable call forwarding, you need to move the Call Forwarding switch from OFF to ON. This immediately enables call forwarding without giving you the chance to enter the number you want calls to be forwarded to. So if you’re frequently changing call forwarding destinations a lot as I do you will often end up setting a wrong destination for a short while until you have clicked the Forward to field and updated the destination phone number.

And, what’s really lame, you still cannot select a number from your phonebook as the destination, you have to manually key in the destination number — I already complained about that two years ago, and Apple still hasn’t fixed this in iOS 6.1.3. Unbelievable for the self-proclaimed leader in usability, Apple! My first cell phone 15 years ago could do that already…