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DMcCunney · 04-16-2016, 08:18 PM

I spend a fair amount of time these days swimming in the Android pool. In the process, I've learned rather more than I wanted to know about how Android devices can fail.

I have a Azpen tablet. It's a generic low end Android tablet from a Chinese manufacturer you've likely not heard of, who appear to actually get their hardware in a OEM deal from another Chinese manufacturer you haven't heard of.

My existing tablet is a 7" model with dual-core 1.4ghz Allwinner23 CPU (an ARM Cortex 7 design), 4GB flash, 512MB RAM, and an 800x480 screen, running Android 4.4.2 Jellybean. The original was a promotional item. Midwest computer retailer Micro Center opened a couple of locations in the NYC area, and a flyer arrived by snail mail offering a 7" Android tablet for $20. At that price, it was an impulse purchase, to let me learn more about Android. The main use would be eBook viewer, for which the specs were adequate. Anything beyond that would be gravy.

I found directions for rooting it on a blog. It took a little doing, because none of the "one-click-root" solutions supported it, but I was able to follow the directions and get a rooted device. This let me remove various built-in apps I didn't want.

It also let me move installed apps to an external card. That can't be done on a normal microSD card. They come formatted as FAT32. You can store data on them fine (like eBook files), but applications can only live on a Linux filesystem. To have apps on the card, you must repartition the card to carve out a slice with a Linux file system, then put the card in the device and reboot. The device will see a new Linux file system and mount it.

Once you have a rooted device and a card with a Linux file system, there are a couple of Android apps that let you move apps to the card. I use one called Link2SD. You install the app as usual to device memory, then run Link2SD. It will let you move the app from system memory to the car, and create a symlink in the root file system pointing to it. Android follows the symlink and runs the app. (You must have a rooted device to be able to make those file system changes.)

I have a 32GB card in the device, so I carved out a 3GB Linux ext4 filesystem and started moving things At this point, the tablet has everything including the kitchen sink installed, and still thinks I have over 425MB of free app storage out of an original 787.

The A727 is getting creaky with age, and I was in the market for a replacement. Micro Center finally showed my local store stocking the A745 model. This is a quad-core 1.3ghz CPU, with the same flash, RAM and screen, running Android 4.4.2 Kit Kat. Retail was $40, with a $10 instant rebate. $30? Sold. I bought one yesterday and brought it home. It came fully charged, powered up, and booted when the power button was held for 3 seconds. Once up, I could turn on wifi, connect to my network, and connect to the Play Store. The installed Google apps I wanted to keep all updated fine. I re-downloaded my preferred launcher and a couple of other things, then disconnected.

Next step was rooting. Azpen has gotten enough market penetration that it's now supported by one-click-root solutions. In my case , I plugged the tablet into my desktop via the supplied USB cable and ran Kingo Root. Kingo identified the tablet as an A745 and suggested rooting it. I said ROOT, and a minute later, I had a rooted device. Install Link2SD and start hacking. All was well till I plugged in the SD card from the A727 and told Link2SD to rebuild the links, to avoid re-downloading and re-linking everything.

I probably should have known better than to try to take that shortcut. The end result was a thoroughly wedged device, stuck in a reset loop. It would not finish booting. It would not power off. I couldn't even get it to the point of displaying the menu that would let me hard reset and revert to factory default status. By this morning, it was totally dead through discharged battery, since it couldn't be turned off. Recharge, and I was back in stuck-on-boot mode.

<sigh> Back to Micro Center for an exchange. The guy at the exchange desk listened to the story, and confirmed it was stuck powered on on boot ("That's running hot!" "Yep. If you know a way to cure that, I'm all ears...") I wanted an exchange, but they were out of A745s. ("We had those for about two hours yesterday...".) They did have an upgrade - a surprise shipment of A746s had arrived. Same basic specs, but with 8GB flash, of which 2GB was available as app storage. $5+ additional cost, but fine by me.

It's up and running, rooted, and in the beginning stages of getting my preferred configuration rebuilt. It's getting a 32GB card, partitioned to provide extra app storage, but this time I'll start fresh and re-download and link instead of trying to use existing links, and with 2GB app storage, I have more headroom before I have to.

Fun, for masochistic values of the term.

______
Dennis

04-16-2016, 08:18 PM	#27513
DMcCunney New York Editor Posts: 6,384 Karma: 16540415 Join Date: Aug 2007 Device: PalmTX, Pocket eDGe, Alcatel Fierce 4, RCA Viking Pro 10, Nexus 7	Android failure modes - collect the whole set I spend a fair amount of time these days swimming in the Android pool. In the process, I've learned rather more than I wanted to know about how Android devices can fail. I have a Azpen tablet. It's a generic low end Android tablet from a Chinese manufacturer you've likely not heard of, who appear to actually get their hardware in a OEM deal from another Chinese manufacturer you haven't heard of. My existing tablet is a 7" model with dual-core 1.4ghz Allwinner23 CPU (an ARM Cortex 7 design), 4GB flash, 512MB RAM, and an 800x480 screen, running Android 4.4.2 Jellybean. The original was a promotional item. Midwest computer retailer Micro Center opened a couple of locations in the NYC area, and a flyer arrived by snail mail offering a 7" Android tablet for $20. At that price, it was an impulse purchase, to let me learn more about Android. The main use would be eBook viewer, for which the specs were adequate. Anything beyond that would be gravy. I found directions for rooting it on a blog. It took a little doing, because none of the "one-click-root" solutions supported it, but I was able to follow the directions and get a rooted device. This let me remove various built-in apps I didn't want. It also let me move installed apps to an external card. That can't be done on a normal microSD card. They come formatted as FAT32. You can store data on them fine (like eBook files), but applications can only live on a Linux filesystem. To have apps on the card, you must repartition the card to carve out a slice with a Linux file system, then put the card in the device and reboot. The device will see a new Linux file system and mount it. Once you have a rooted device and a card with a Linux file system, there are a couple of Android apps that let you move apps to the card. I use one called Link2SD. You install the app as usual to device memory, then run Link2SD. It will let you move the app from system memory to the car, and create a symlink in the root file system pointing to it. Android follows the symlink and runs the app. (You must have a rooted device to be able to make those file system changes.) I have a 32GB card in the device, so I carved out a 3GB Linux ext4 filesystem and started moving things At this point, the tablet has everything including the kitchen sink installed, and still thinks I have over 425MB of free app storage out of an original 787. The A727 is getting creaky with age, and I was in the market for a replacement. Micro Center finally showed my local store stocking the A745 model. This is a quad-core 1.3ghz CPU, with the same flash, RAM and screen, running Android 4.4.2 Kit Kat. Retail was $40, with a $10 instant rebate. $30? Sold. I bought one yesterday and brought it home. It came fully charged, powered up, and booted when the power button was held for 3 seconds. Once up, I could turn on wifi, connect to my network, and connect to the Play Store. The installed Google apps I wanted to keep all updated fine. I re-downloaded my preferred launcher and a couple of other things, then disconnected. Next step was rooting. Azpen has gotten enough market penetration that it's now supported by one-click-root solutions. In my case , I plugged the tablet into my desktop via the supplied USB cable and ran Kingo Root. Kingo identified the tablet as an A745 and suggested rooting it. I said ROOT, and a minute later, I had a rooted device. Install Link2SD and start hacking. All was well till I plugged in the SD card from the A727 and told Link2SD to rebuild the links, to avoid re-downloading and re-linking everything. I probably should have known better than to try to take that shortcut. The end result was a thoroughly wedged device, stuck in a reset loop. It would not finish booting. It would not power off. I couldn't even get it to the point of displaying the menu that would let me hard reset and revert to factory default status. By this morning, it was totally dead through discharged battery, since it couldn't be turned off. Recharge, and I was back in stuck-on-boot mode. <sigh> Back to Micro Center for an exchange. The guy at the exchange desk listened to the story, and confirmed it was stuck powered on on boot ("That's running hot!" "Yep. If you know a way to cure that, I'm all ears...") I wanted an exchange, but they were out of A745s. ("We had those for about two hours yesterday...".) They did have an upgrade - a surprise shipment of A746s had arrived. Same basic specs, but with 8GB flash, of which 2GB was available as app storage. $5+ additional cost, but fine by me. It's up and running, rooted, and in the beginning stages of getting my preferred configuration rebuilt. It's getting a 32GB card, partitioned to provide extra app storage, but this time I'll start fresh and re-download and link instead of trying to use existing links, and with 2GB app storage, I have more headroom before I have to. Fun, for masochistic values of the term. ______ Dennis Last edited by DMcCunney; 04-16-2016 at 09:54 PM.