[GUIDE][07/07/11]How to Partition your SD Card

With the GingerSense ROM’s being the new hotness right now, there is a overwhelming amount of questions about partitioning. This guide is intended to help anyone that may want to partition their SD and not sure where to start. This information was gathered from The Mynions and posted several times in Myn’s Warm2p2 and Project Synergy threads. This guide was created while using Project Synergy RC1, which runs a CM script that has been modified. Come get assimilated!

Please, READ first before attempting if you are a noob, it’ll save you some gray(grey) hair. I am in no way responsible for any issues you have for following this guide, use at your own risk.

WARNING: This will erase EVERYTHING on your SD card so please transfer the contents of your SD card to a computer or external hard drive PRIOR TO starting this procedure.
1. Boot into recovery (hopefully you have amonRA v2.3)
2. Select "Partition SD Card". You will be prompted to set an amount for the SWAP, ext2 and FAT.
3. Enter zero for the SWAP size, 1024 or 2048 for ext2 and the rest for FAT*
4. After the process finishes, select "Upgrade ext2 to ext3"
5. When the process is complete, go to the wipe menu and wipe EVERYTHING in it.
6. From the main menu, select USB-MS (your phone should be connected to your PC) and copy the Synergy ROM(or your ROM of choice) to the root of your SD Card.**
7. Flash Synergy(or your ROM of choice)
8. Be patient at initial bootup because it can be quite long.
9. I recommend that your 3rd party apps be installed freshly from the market initially. They will automatically be place in the ext3 partition. You can verify it by checking to see that they are listed in the /system/sd/ folder which itself contains 3 folders: app, app-private & dalvik-cache.

After you have followed the directions to partition your card, followed by a flash of the rom and installation of your 3rd party apps & games, go to Menu-Settings-SD & phone storage and check your available internal storage space. If it is 300+, it is safe to assume that the built-in a2sd is working. Furthermore you will need a system level file manager to see the /system/sd/ folder. The Astro File Manager cannot see it.

*These sizes are only used for reference, but excellent choices. You may want to consider a swap partition, even though the stock HTC kernel does not support it. Future kernel development may take advantage of swap and doing so now can save the hassle of re-partitioning later. Food for thought.
**This guide was done while using THE Project Synergy ROM, however it should work across the board.

Hope this helps.


Special thanks to dougjamal, lowetax and all the Mynions helping out around the world (We Global!)

F.A.Q.

Q: Do I have to partition my card?
A: No. The main reason people partition is to take advantage of Apps2SD script. This allows for more internal memory and, depending on which version, control over various system settings (Ex.: http://xdaforums.com/showpost.php?p=7021317&postcount=1).

Q: Do I need to format my SD Card after partition?
A: Actually, no. Will it hurt if you do? No. Creating partitions wipes the SD Card, sets up logical drives(partitions) and formats the space(or you couldn’t write to it). The time consuming part of partitioning is the Card formatting.

Q: Can I run the stock/android A2SD after partitioning?
A: No. The Apps2SD script is different from stock. Using the stock A2SD will give you problems.

Q: Can I do a nand restore after I partition?
A: No. Your SD card's file system has changed and you may experience unfavorable results.

jminor4326 said:

sorry you can't read my mind. I'm trying to understand the methods of putting apps onto the SD card giving more room on internal memory. There is the app APPS2SD that allows apps to be moved to the SD card. Then there is the method Dredz shows using RA that puts apps into SDEXT automatically using a script (I think). Then I think there is the Dark Tremors apps2sd method.... correct? The partition Dredz shows us cannot use the APPS2SD - correct? And some ROMs can use the RA partition and others can't ... correct? Then there is the Dark Tremors method... what is that?? Can someone please explain the difference between them all. Thanks, I'd really appreciate an explanation.

Click to expand...

Click to collapse

Ok, I must really be either bored or like you, because this is my second time writing this...

For those that are more technical, forgive my oversimplification, and feel free to chime in and correct as necessary...

It may help you to think of your phone's (application related) memory as 3 types:
Internal – this is the smallish amount of flash memory built into the phone, it's precious and seems to go quickly if you aren't careful.
“SD Card” – this is the memory you are able to see when you connect the phone to your computer, it's cheap, expandable but usually slower and quirky (from an app standpoint), it's also where apps go when you use the 'move to SD' function
SD Ext3 – This is a small partition on the card that you made if you followed the directions of the first post. It comes at the expense of SD Card space, but it's worth it...

On a 'normal'/stock install, most apps will try to install themselves into your internal memory. This is good in the fact that the internal memory has great read/write speed and bad that you don’t really have a lot of it. Google addressed this in android 2.2 (froyo) by allowing apps to be installed/moved to the sd card. You can do this yourself by menu>settings>applications>manage applications. Select one, and odds are, it says, 'move to SD card'. This would let you move most of it's data to a special folder on the SD card, saving precious internal memory. The downside is that it's a pain to do one at a time... That's where all those apps in the market apps2sd, apps 2sd pro, blah blah blah, come in. They make it easy to move lots of apps back and forth to being installed on the sd card and/or internal memory. Technically, it's nothing you can't do by hand, but they make it nice and pretty. Another downside to this method is that not all apps can get moved, and some that do act funny when they are (widget related apps especially act wonky)...

So to address this issue (and the lack of ability to do so pre-froyo), some people much smarter than you and me figured something out . They worked it so you could make a small partition on the pysical SD card that acted more like internal memory. So you install apps as if it's internal, but it's really on your physical card. It's the best of both worlds, the lack of headaches associated with internal memory, but the large size from the card. But, in order to make it work, a script is run to make android treat part of the sd card as if it's internal memory. One of the more popular is the CM a2sd script. It's built into lots of ROMS, including Synergy. When you install the rom, it checks to see if you have this partition on your SD card, and if so, it automagically lets the script to do it's thing. That's what you made in the beginning... a small ext3 partition that effectively expands your internal memory when used in conjunction with the script. They work together, useless in and of themselves. But one of the great things about android is evolution...

So, in addition to apps, one of the other things that (normally) resides on your internal memory is the davlik cache. Google the specifics, but this is what helps your apps run, and run well. The possible downside of using the ext3 partition and a2sd script is that this cache ends up on your physical sd card. Assuming you have the stock card, read/write is going to be slower on that, than the true internal memory. So, some other folks, again, much smarter than you and me, came up with a variant of the script (DT a2sd) that allows you to force the cache back onto the true internal memory. So even though there is less 'true' internal memory, the cache is in the fastest place, so it's a performance tradeoff. The DT a2sd does some other things, but this is the relevant point here. There is even an app on the market that lets you turn some of the features of the script on/off , including forcing the cache location. Since the CM a2sd and the DT a2sd do pretty much the same thing, running both at the same time is problematic, hence the warnings...

If you want to see the whole thing in action, install a ROM that includes the script and open Titanium Backup, on it's first page at the bottom, it breaks down the memory types for you and how much they are used. You'll see that as you add apps, they will reside on the ext3 (called SD a2sd in TB). Ultimately, you are going to have to make the search button your best friend, and put a few hours or so into educating yourself, but hopefully, this gives you a basic framework to go with. Once you become knowledgeable, be sure to pass it on to someone else who may have a question or two.

Hope this helps, and I reserve the right to be completely wrong about everything stated here and will happily accept corrections.

wings9130 said:

I'm a little confused about this. If you partition your card you will get more internal memory but it will be used on the card on one of the partitions? Also if you start your rooted phone without your sd card will it still bootup properly? Also im wondering if it needs the rom file that is on the root of the sd card to bootup the phone with the custom rom properly?




I'm still a little confused by what you mean by default A2SD. Does that mean after partitioning the card or something else?

Click to expand...

Click to collapse

Some ROMS have a2sd built in. There are two main players in the a2sd game right now. Theres CM a2sd (cyanogen mod) and DT a2sd (Dark Tremors). Synergy has the CM script built in to utilize the CM a2sd. This is automatic IF and only IF your card is partitioned to take advantage of it. If your card is not partitioned your apps will go to internal memory as well as the Dalvik cache going to internal memory. What this means is because the ROM is so large you will have a very low amount of internal storage remaining for your apps. Once you get below 50mb of internal you will begin to get the low memory warnings. Hence if you partition your card BEFORE you flash the ROM all of your apps both system and downloaded will automatically go to the SD card. On your initial boot you will have anywhere from 350 to over 400mb of available internal memory.

Now as stated there is the DTa2sd script available in the Synergy updater. You can flash this right over the built in CMa2sd. What benefit does this have you ask? Well this puts the Dalvik cache back into internal memory. For some including me, this makes the phone run faster with no lag even though I use a Class 6 32gb SD card. YMMV. Be advised however you will notice that instead of the 300 to 400 available internal it will be anywhere from 200 to 150. That's because the Dalvik is taking space on the internal memory. However, even when you install new apps, this number will change very little. Over time you can wipe the Dalvik to free up space but really not necessary.

While no one says it is imperative to partition your card, it is not the daunting process it seems. The hardest and most time consuming part is copying your files to your computer to save them BEFORE partitioning. Depending on how much you have on your card, give your self about an hour free time and follow the directions. Use AmonRa if you don't have it. For months I was a diehard Clockwork user but the switch is well worth it. Taking the time to partition your card and use either the built in utility or the DT script will save you much time and will forever avoid the low memory message downloading as many apps as you want (unless you download every app on the Market).

Got it?

Since the stock Kernel doesn't support Swap, after first boot, go to terminal, type Su then enter, then type a2sd check.

It will probably say swap not running at boot. It should say that the partition is present and a bunch of other things.

Next type a2sd swappy10 then enter.

Now type a2sd reswap.

If you get an error, you can run a2sd reinstall which will reboot your phone.

Go back to terminal and type Su and then a2sd reswap.

Should be good to go, but you have to run the reswap after every boot til we get custom kernels.

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