Possible to boot A500 from external SD card?

Do you have something on your mind that is not related to the devices below? You should ask us or the community.

Possible to boot A500 from external SD card?

Postby bakaneko59 » 27 Mar 2015, 20:28

Does anyone know if it's possible to boot the A500 from an SD card rather than the internal RAM? I've seen the capability with other tablets (Nook Color, ASUS Transformer, etc.). It seems to me that accessing my external class 10 SD card is much faster than accessing the internal memory so I figured running the entire system off of the external SD might produce a performance boost. I don't mean just moving some apps there like apps2sd - I mean running the entire OS there.

In the case of the Nook Color it seems to be inherent in the hardware. If the SD card is prepped properly it will boot from it rather than the internal memory. This allows you to have two different ROMs available so you can test out one without goofing up the other. In the case of the TF701 Transformer some XDA ROM builders have moved the OS to the external SD due to the poor performance of the internal RAM.

Anyone ever looked into this? Maybe a small mod to Skrillax's boot loader or a small bootloader on the SD card called update.zip (since the system seems to run that if it's present.) I'm not an android dev so I don't know the ins and outs. Just curious to know if it might be possible.

Thanks.

Sent from my A500 using Tapatalk
BakaNeko59
Acer Iconia A500 Tablet
(ReFLExxx or Thor Lollipop depending on how I feel)
Samsung Galaxy S III
(heavily tweaked stock)
Tons of other stuff running Win7-10, Server 2012, Linux, etc...
User avatar
bakaneko59
Junior Owner
 
Posts: 24
Joined: 16 Dec 2011, 19:43
Reputation point: 0
Junior Owner

Re: Possible to boot A500 from external SD card?

Postby thor2002ro » 27 Mar 2015, 20:38

sure modify fstab and installer
_________________________
Dropbox! So useful for sharing files among multiple computers and ANDROID Phone get 2.30GB storage -> LINK

++++++++++++
Samsung Galaxy Note - Drowned

Samsung Galaxy Note 2 - Sold

Oppo R5s - Sold

LG V10 :)

Acer ICONIA A500 TAB WIFI Only
FW: Tegraowners 6.0 internal ROM
Recovery: touch recovery 2.0b

Asus Google Nexus 7 Wifi
FW: Tegraowners JB-MR2 ROM
++++++++++++
If I did something you liked HIT rep + button (: and Image $Image to BEER FUND
User avatar
thor2002ro
Global moderator / Dev Team
 
Posts: 10042
Joined: 14 Aug 2011, 23:31
Location: 127.0.0.1
Reputation point: 594
Junior OwnerJunior OwnerJunior OwnerJunior OwnerJunior OwnerJunior Owner

Re: Possible to boot A500 from external SD card?

Postby Skrilax_CZ » 29 Mar 2015, 13:00

You can boot the system off sdcard without modifying the bootloader, you just need your boot image to be present in internal sdcard, that's all.
User avatar
Skrilax_CZ
Senior Owner
 
Posts: 181
Joined: 09 Feb 2012, 13:59
Reputation point: 272
Junior OwnerJunior OwnerJunior Owner

Re: Possible to boot A500 from external SD card?

Postby agarn3t » 30 Jun 2015, 18:38

Skrilax_CZ » 29 Mar 2015, 07:00 wrote:You can boot the system off sdcard without modifying the bootloader, you just need your boot image to be present in internal sdcard, that's all.



My A500 froze up a few months ago and I tried several things to get it working. I finally got it to work again by baking it in the oven to reflow the solder on what I believe was a loose nand chip - a common problem on the A500 from what I read. After baking it, and about 50 tries using NVflash, I was able to get HC installed and it was working fine....except....I can't flash any updates. I'm stuck on HC which is really outdated for installing new apps. I tried several ways of flashing a new ROM ( update.zip, fastboot, ... ) but I always get an error. I believe the nand may be damaged or there may still be a few loose solder joints.

Anyway, I was really interested in this thread because if I could boot my A500 from the SD card shouldn't that solve the nand problem ? If it does work, I believe there are many other people with problematic nand chips that could benefit from this. The only thing is my tablet is not running a current rom and I'm a bit of a newb so I don't know how to go about Skrilax_CZ's suggestion. Also, if booting from the SD card works, would it be possible to create a generic KitKat or Lolipop SD iso image and just load that on the card or would there be something in the iso making it proprietary to each A500 ?

Thanks
User avatar
agarn3t
Junior Owner
 
Posts: 2
Joined: 20 Oct 2014, 05:39
Reputation point: 0
Junior Owner

Re: Possible to boot A500 from external SD card?

Postby agarn3t » 02 Jul 2015, 16:35

Skrilax_CZ » 29 Mar 2015, 07:00 wrote:You can boot the system off sdcard without modifying the bootloader, you just need your boot image to be present in internal sdcard, that's all.



I found something over on XDA posted by lexelby. He was able to boot his Asus Transformer from SD but, from my limited understanding of this, it required that the SD card be partitioned and then the proper files be extracted from a stock ROM and then copied to their respective SD partitions. I believe his method also required that the existing internal SD card be accessible for some files ( radio/modem). Here is his explanation :

"I took sdbags's stock zip (4.3) and extracted it on my computer. I used unmkbootimg to extract the initramfs.gz and kernel.gz from the boot.img in the ROM. I unzipped the initramfs and un-cpio'd it, then modified macallan.fstab to refer to /dev/block/mmcblk1p1 for /data, p2 for /system, and p3 for /cache. I also modified init.macallan.rc to avoid having it try to make filesystems on the EMMC -- I want it not to try touching the EMMC at all.

Next I rebuilt the initramfs.gz. I bought a good quality class 10 microsd and partitioned it on my computer with 3 primary partitions, one for /data, one for /system, and one for /cache (about 2GB and 1GB for /system and /cache). I made ext4 filesystems on all 3 partitions, mounted p2, and copied the rom over and installed it by hand using the updater-script as a guide. Then I unmounted and popped the SD card into my TF701t.

To boot it, I put my tablet into fastboot mode. I booted the kernel and ramdisk using 'fastboot boot' -- no need for kexec from recovery. I can do this without any reliance whatsoever on the internal EMMC. It took awhile to boot up, but it booted first try. The app drawer was a bit slow to come up, but I'm pretty happy I get to use my tablet at all! This whole process turned out to be MUCH easier than I expected it would be, and I'm quite confident I could do this to boot any ROM I wanted. I only use stock because of driver issues with my bluetooth keyboard."

Is this the right path to take for the A500 ? Any input on this would be greatly appreciated.

Thanks
User avatar
agarn3t
Junior Owner
 
Posts: 2
Joined: 20 Oct 2014, 05:39
Reputation point: 0
Junior Owner


Return to What's Your Question?

Who is online

Users browsing this forum: No registered users and 1 guest

cron
x

#{title}

#{text}