Bootable ext4 Micro SDHC card reported as “Damaged SD card” by Android phone

TL/DR – if you have ext3/4 partition on your Micro SDHC card (e.g. you boot some Linux from it) and then try to put this card into Android phone, it will complain about “Damaged SD card” until you erase (zero out) bootloader from ext3/ext4 partition.

 

Android phone complains about damaged sdcard after bootloader installation. But not just any bootloader. It actively dislikes any bootloader on ext3/4 partions. It complains and refuses to mount sdcard. If you force mount in terminal/ADB - it will mount, but bootloader will be corrupted (do not know exactly why, but has to do something with security and signing of Android system bootloader). My card is multi-partition, and while I mount PRT1 (FAT32), Android corrupts Partition Boot Record (PBR) on PRT4 (EXT4). To avoid this problem I zeroed out PBR on PRT4 (where Linux resides) and Android immediately stopped compaining about the card. Mounts it, scans it, uses for camera/gallery storage, etc.

NOTICE AGAIN: ZERO OUT EXT3/4 PARTITION BOOTSECTOR to allow mounting of FAT32 partition in Android. Strange, I know. I think Android is crazy cautious about EXT3/4 bootloaders, to prevent booting unsigned ROMs from any EXT3/4 filesystem, no matter if it is on internal or external sdcard.

I couldn’t google up anything on this topic, and spent couple of days understanding and then solving this issue. Here goes more detailed explanation. Hopefully it saves time to other people trying to read bootable FAT32/EXT4 card in Android (keywords: USB multi-boot, Micro SDHC, Android, SD Card is Damaged, bootloader, grub, mbr)

I use Sandisk Ultra Micro SDHC (UHS-1) 64 GB card in my phone (LG Optimus 3D, ICS 4.0.4) and in compact Lexar USB3.0 card reader on a keychain.

On Android, I use excellent app DriveDroid to expose bootable IMGs to PC via USB cable (mostly Windows Defender Offline x32/x64, and Windows 8 Install/Recovery). But I also use USB 3.0/MicroSDHC reader with  multiple ISOs, Porteus Linux and a real installation of Linux Mint on EXT4. It is fast enough. Boots in a minute. Speed is OK, feels like a slow laptop HDD of 2010.

Card is partitioned into:
MBR  with BOOTMGR (here and in other cases, installed with BOOTICE (free Windows app) 
PRT1: FAT32 -50GB with BOOTMGR (NT6) - Largest partition for data - compatibile with most devices
PRT2: NTFS - 1GB NTLOADER*
PRT3: NTFS - 1GB NTLOADER*
PRT4: EXT4 - 12GB - used to be GRUB2, now empty boot sector

*PARTITIONS 2 and 3 are small stubs between FAT32 (max space) and EXT4 (limited space at the end of  card). I figured that one day I might want to reduce FAT32 and experiment with another or two partitions, without having to move EXT4. I guess PRT2 and PRT3 are not relevant further to this topic.

I played quite a lot with the PRT1, it boots Windows 8 BootMgr, and from there I have added syslinux and grub4dos and can go between them, chainloading each other in circles.  What is interesting, is that I can put any bootloader on FAT32 (PRT1) and it will not affect my card when I put it into Android phone.

THE PROBLEM BEGAN AFTER INSTALLATION OF LINUX ON PRT4(EXT4). Android refuses to mount the card. I forced it through terminal with
su
mount -t vfat /dev/block/mmcblk1p1 /mnt/sdcard/_ExternalSD

File explorers then can see the card but message about Damaged SD Card still hangs there in notifications. When I unmount the card and try booting Linux, it freezes silently. Turns out bootloader of GRUB2 in PRT4 is corrupted.

In order to solve this problem, I booted Mint's vmlinuz/initrd directly from GRUB4DOS on PRT1 and reinstalled GRUB2 on PRT4, then used BOOTICE to copy PBR from EXT4 partition (512 bytes) and save it into file on FAT32. Now I can boot it from BOOTMGR directly into GRUB2.mbr file and use Linux. Then, I used BOOTICE's sector editor functionality, to fill first sector (512 bytes) of PRT4 with zeroes. After doing, this, Android stopped compaining about the card and happily mounts FAT32 partition.

Enjoy, and share in the comments your weird and geeky setup. I am really interested in miniscule and versatile computers and what you use them for.

Just bought Motorola XT720 from Expansys

Just received by DHL. Bought at Expansys.lv (Latvian version of expansys.co.uk). Phone was delivered from warehouse in Marseille, France.

Some notes – very nice build quality, rubberised metal on the backside, nice display, TFT with mirror underneath, so it looks ok in the direct sunlight. Strange, you cannot work with this phone without SIM, only emergency calls allowed. Another negative, about body construction – the blue border around lense (2nd picture here) is very razor sharp and collects particles of my pocket cloth. Finally, a nice touch, 8GB SD card is included.

I did not check processor speed, but it is slower than Samsung Galaxy S that I used previously, so maybe it really is 550MHz, but Motorola promised to up that to 720MHz in the new firmware and to upgrade OS to Android 2.2.

re: last photo here – in the top right corner you can see indicator of filming mode (camera in this case). I expected that it is sensitive button, but, alas, I cannot make it switch modes by touching any of those indicators. You need to go to on-screen menu to change modes.

Hack your way into Google Buzz

If your mobile phone is not Android or iPhone… or your gmail still does not have Google buzz folder, you still can get into buzz, albeit only mobile version. Use Firefox extension – UserAgentSwitcher. Choose iPhone3.0 profile, go to buzz.google.com.

You can also buzz from symbian (and I presume winmo, although I haven’t tested it) goole maps (v.4.0) which was updated yesterday on google servers. Works on Symbian s60v5.

Google Maps for Symbian update, Opera Mobile 10 Beta 2

Google Maps 3.3 now supports syncing of Nokia Landmarks and Google Maps favourites between handset and the mighty google cloud. Looks like another nail into the coffin of Nokia Maps?

Opera Mobile 10 Beta 2 for symbian has got Opera Sync and Download manager, but the sweetest thing comes from the fixes to memory management and rendering speed. It was quick on Omnia HD i8910, and it is (subjectively) twice faster now.

Opera Mobile 10 Beta for Symbian

This is important. This is hilarious if you have got fast symbian phone with lots of RAM. Opera Mobile 10 is here. Installed it on my Omnia HD i8910 and immediately  tweaked RAM cache to some 50MB. Running well and not getting any “low memory” erros, like poor N97 guys. :)

It’s fast. It’s fucking Ajax compliant.

Gmail. It opened gmail in “standard view” and works fast.

Google Reader also opened in “standard ajaxy” mode. Wow.

Google Wave opened with errors. Not usable.

Youtube. Hmm, it doesn’t play youtube yet, but I have heard it from Opera some time ago, that Flash will be supported.

Friendfeed  works, as does Facebook.

What is best sync solution for Windows?

I am looking for a best Win program to sync my numerous laptops, media pc, and hopefully, my mobile, with selected folders on my 24-hrs file server running on Windows 7.

After googling and reading a bit, I identified

• Unison, and DeltaCopy – as Windows GUI for the famous rsync. Should be simple and mature.
• Folder share (MS Live Sync) – free solution from Microsoft. Should be pretty simple too.
• Synplicity,  Sugarsync, Dropbox – other well established programs. These seems to provide online storage for files, and any reasonable amount (over 2 or 5 GB for different programs) will cost money. Since I already have own always-on server, I feel that I do not need their service.

So, I will be installing and trying Unison, DeltaCopy and Foldershare.

Going to Ukraine

I am going to spend my vacation in Ukraine, and will go there for two weeks starting from this Thursday, 19.6.

I am going by car,  route will be 2000km and will take 2 days driving in each direction. Here are 2 parts of the route.

First part is Riga - Lithuania - Poland. 845km. Plus time lost on Ukrainian border and another 140km in Ukraine to the hotel in Lutsk. I had to plan it in Google Maps. Actual navigation will be with TomTom 6.02 on Nokia N82 (Garmin XT mobile maps as backup).

2nd day will be only 900km. This one was planned in Garmin mapsource. Actual navigation will be by Garmin Mobile XT. (Nokia Maps 2.0 as backup).

There are two options for this day - going through Vinnitsa or going through Zhitomir. Both are same distance and I am trying to obtain more feedback in the excellent (russian speaking) community of autotravellers at AutoUA.

Apart from mentioned programs I still have maps of Ukraine and Ukraine largest cities in YandexMaps cache, SmartcomGPS and of course there is Google Maps mobile and MGMaps, but those require GPRS, which I will only connect when I arrived in Kherson and will buy local SIM card with unlimited GPRS.

My new Nokia N82 Black and iPhone Google Reader

I waited for several months for the black version of N82 to become available and this Monday I finally got one. I am delighted with it. Build quality is superb, despite of what people commented on silver version. Firmware is mature, and there is ton of free RAM to run a dozen of apps at the same time. It is quick too. I usually keep open 2 gmail apps, fring, palringo,and several tabs in browser (google reader, etc.) Today I received a call, and while speaking via bluetooth headset, I opened google maps and checked satellite view of the location that was discussed. All of it without a hitch. It worked really well with my home WiFi connection in parallel with GSM call and bluetooth headset.

Keyboard is a treat too, surprisingly so.

I will not comment on excellent photo and video quality, because many people have done it already. Suffice it to say, that this is the first truly multimedia and multitasking computer from Nokia in the smallest form factor and at affordable pricepoint. Prices have dropped from 600 EUR on launch to 350 EUR now. Way to go, Nokia.

Autorotation is good for comfortable photo viewing. Youtube playback over Wifi connection is perfect.

Coreplayer 1.2 plays anything you can throw at it. Now I only need a 16 or 32 GB card to hold my media.

GPS easily picks up inside my flat, something even my SIRF3 bluetooth module couldn't deliver.

This is also a device that finally can run QuickOffice smoothly and I even splashed on buying 5th version with Office 2007 support.

And finally, S60 browser has enough memory to shine opening several heavy tabs at once.Which leads me to the last point for today - it works really well on iPhone version of Google Reader, making it so easy to follow my feeds. I attached some screenshots of this. Now, you can view post summaries within the same window, and if needed it opens full posts in new tab. I abandoned Opera now. But if the Opera 9.x for S60 will deliver promised improvements, then this phone will replace my Everun UMPC for 99% of my mobile computing needs.

Thank you, Nokia. This is a great device. Now, that my cigar is starting to burn my fingers and cognac glass is empty, I will finish this post, written on Nokia N82, and will go inside. Good night.

Google Maps enables MyLocation in Latvia

Do not know when this happened, the MyLocation feature of Google Maps, that guesstimates approximate location of the user without use of GPS, but rather, relying on cellular tower location database, is active now. I think I tried it couple of months ago, and it was not active at that time. Now, it still is pretty rough. But it is good for learning locations of nearest cell towers of your operator. After checking my location 3 times, within different rooms of my flat, I learned that I am located between 3 cells and my location indicator will show different points on the map for each room. Nice. Certainly not good for a phone battery life when handset is forced to switch between different cells, trying to find one, which is not as bad as the current one.

See realtime slideshow of pictures that people upload to Blogger at play.blogger.com

 

The experience is tantalizing... Even though it is recommended to use it as screen-saver, a single geek can enjoy it with a cigar and whisky on a Friday night... Plus, you may click on any interesting picture and it will open the related blog. You may find some new interesting blogs this way. Enjoy.