[HOWTO] [REF] Prevent Bootloops when using App2sd+ / Data2sd / whatever2sd-ext - Optimus One, P500, V General

Above the hood​
Well today I intended to answer voyager's problem which was stated in the interactive data2sd thread located here http://forum.xda-developers.com/showthread.php?p=23744977#
and then i think that after i have gathered so much information from the other parts of the world into this little post it would be a waste if it is pushed away by regular posts in the thread. so, i opened this thread here in the general forum so all people with similar confusion can read about it.
YES, there are SO MANY WORDS TO READ. but in order to use a2sd+ or data2sd+ you MUST read them all
you will never know how frustrated i was when i was encountering the bootloop problem for the ENTIRE month.​
my report thread - http://forum.xda-developers.com/showthread.php?t=1239063
my help-seeking in the darktremor thread which was answered by famous developer temasek - http://forum.xda-developers.com/showthread.php?p=17232233​
my target was originally voyager the person but now its to all of you, please ignore my incorrect pronouns, if there are any ​
OH FINALLY i luckily found the very useful reference that i have read before!! after reading these you will understand everything
tobydjones said:
Some phones, eg the Desire, don't have enough internal memory (NAND). A2SD and other 'init.d scripts' fool Android into storing various things on the SD card instead of internal memory to free up space. They can move either apps, the Dalvik cache (a pre-compiled copy of each app) and/or app data. And they can move them to either the 1st (only) partition of the SD card (formatted as FAT or FAT32) or a 2nd partition of the SD card (formatted as ext3 or ext4).
As there's so many different scripts doing different things, I had to make a table to sort it all out. Please let me know if I've made any mistakes, or if you can answer any of my questions in italics.
script ................ apps . Dalvik . data .. comment
---------------------------------------------------------------------------------------------------------------
A2SD pre Froyo ........ SD ... int .... int ... Made to move app data to SD {or was it already ext?}
Froyo A2SD/"move to SD" SD<1>. int<9> . int ... Built in
Gingerbread A2SD ...... SD.... int .... <6> ... Built in. As Froyo but a bit more space.
apps2sd app (on market) ....................... App to make Froyo/Gingerbread "move to SD" easier, not a script
Force2SD (on market) .. ....................... As apps2sd + move system apps>SD {does apps2sd also do this?}
A2SD/AS2D+ (or apps2SD) ext<8> in/ex<2> int ... Various implementations<7> some move Dalvik (manual/auto)
Darktremor A2SD/DT-A2SD ext .. in/ex... int ... Move Dalvik. Used to be auto, now command line (or use A2SDGUI)
MIUI_Au PC-A2SD ....... ext .. ext .... int ... Allows android to boot if SD Card broken/removed. With logs
Link2SD (on market) ... ext .. ext .... <6> ... Moves apps individually
Sibere DATA2SD ........ ext .. ext .... ext<3>. Moves whole /data folder to ext for more space <4><5>
DATA2EXT .............. ext .. ext .... ext ... {another implementation of DATA2SD? how does it differ?}
data2whatever/DATA2WE . ext .. ext .... ext ... Can use ext2-4 plus variety of unusual filesystems eg B(RT?)FS
Notes:
<1> The SD card is mounted very late in the boot up process, so background apps and widgets won't work. Also apps on SD aren't available when SD card is used as a disk ('mounted')
<2> Dalvik on SD/ext may wear out SD card a bit quicker {not a big issue compared with int memory wearing out?}
<3> Data on ext wears out SD card faster because of data writes {how much of an issue is this?}
<4> Data2SD on Sense ROMS - possible corruption during battery pull or forced reboot
<5> Data2SD on ASOP ROMS - corruption when turning off phone due to unclean dismount {or is this fixed now?}
<6> GB doesn't move all of data, but does move app libs (/data/data/<appname>/Lib)
<7> There's a lot of confusion what AS2D, AS2D+ and apps2sd refer to, and the distinction between them, as those names been used for many things, including an app on the market! The + appeared after Froyo was released and often means the Dalvik cache can be moved (not always automatically)
<8> Unlike moving apps to SD, you can move widgets to ext, and apps are available when SD card is used as a disk
<9> If Dalvik cache is on int, number of apps is still limited as pre-compiled copy of each app held in cache
Updated 01/10/11. Thanks to rootSU, fllash & rmcsilva for corrections and additions
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neoKushan said:
Ok, so here's the deal, in a very longwinded way that should hopefully explain everything and answer ALL questions.
You have an SD card in your phone and, a bit like normal PC Hard Drives, you can "partition" them (split them into two or more sections of different filesystems). Normally, your SD card is just one big FAT32 partition, which is fine for storing your pics, messages, emails, etc.
Now, other then your Phone's SD card, your phone will have its own internal flash memory (or "NAND") storage. Tradditionally with Android, you could only install applications to this NAND storage, you cannot install them onto your SD card. So if you have an empty 32GB SD card, but only 5Mb of internal phone storage, you still wont be able to install many apps, if any at all.
This was done to protect the apps from things like piracy - it's not easy to access the location where apps are installed on your phone's internal storage (normally impossible without root), so you can't for example buy an app, copy it, refund it, then install it again.
Still, this is no good for those of us who like to install lots and lots of apps, legitimately, as we run out of internal storage very quickly.
So Google came up with a way to install apps to the SD card. A folder is created called something like .android_secure and this stores (I believe) encrypted versions of applications, but there's a few catches:
1) Apps aren't automatically stored here, you have to manually "move" them
2) Not all apps are capable of being moved, in fact most apps aren't, the developer needs to update their app and allow it. Some apps aren't and wont be updated and some developers may not want to allow it for whatever reason.
3) Not all app data is moved, most of it is but some data is left on your phone so many people still run out of internal storage quickly.
4) You can force ALL apps to be moved to this area by default, but it breaks incompatible ones - such as Widgets, which are unable to load due to the SD card not being "prepared".
So that's Froyo's version. Before Froyo existed, some very clever people came up with a thing called "Apps2SD". Remember I said that your SD card normally is one big FAT32 partition? Well, Apps2SD works by having your SD card patitioned into TWO filesystems. A normal FAT32 partition for your usual stuff and a secondary "EXT" partition. EXT is just a filesystem, like FAT32 or NTFS, but it's the filesystem used by Android internally. The SD card is normally FAT32 because it's a "universal" filesystem, that just about any machine will be able to read, whereas EXT filesystems are generally Linux only, but I digress.
EXT has several different versions. The most common one you'll see is ext3. The main difference between ext2 and ext3 is "journaling", which is just a fancy way of saying that should an operation (such as copying, writing or reading) be interrupted unexpectedly (say, by you turning your phone off), then no data should be lost or corrupted. You know how when you turn your phone on, it says "preparing SD card"? It takes a few minutes, but what it's actually doing is checking that the FAT32 partition hasn't been damaged, because FAT does NOT have journaling. If you used a computer back in the Windows 98 days, you may remember that lovely blue "Scandisk" screen that had to run every time you didn't shut your computer down correctly - that's the same thing. But then Windows 2000/XP came along with NTFS, which also has journaling, meaning you had less chance of loosing data. But I digress once more.
So you have your SD card partitioned into EXT and FAT32. Generally it doesn't matter if it's ext3 or ext4, but you don't get any real advantage with ext4 over ext3 in this instance. Apps2SD then runs a special script on your phone which "symbolically links" the folder from your phone's internal storage where your apps are normally stored, to the ext partition on your SD card. A symbolic link is a bit like a shortcut for folders, except it's transparent to the OS: In other words, Android doesn't know that when it's installing it's apps to the internal phone storage, it's actually being stored on the SD card. This effectively boosts your internal phone memory from the previous 5mb that you had in my example above, up to whatever size you made the ext partition on your SD card (often 512Mb or 1Gb, but it depends on how many apps you install).
Plus, because it's "journaled", it doesn't need to be "prepared", meaning it's ready to go as soon as the phone starts - so your widgets and apps work immediately (unlike "forced" Froyo Apps2SD, where widgets disappear).
The catch with Apps2SD is that whatever space the ext partition takes up is taken away from the SD card. So if you have a 4Gb card (with something like 3.5Gb of actual storage) and you make a 512Mb ext partition, your SD card will "shrink" to 3Gb. The space isn't actually lost, it's just being used by the ext partition. If you reformat your card, you'll get it back.
Finally, there's a difference between "Apps2SD" and "Apps2SD+". Remember I said that your apps are stored on a special folder inside your Phone's NAND storage? Well, that was a bit of a lie. It's actually stored in TWO places. There's a second area which is called the Davlik Cache. You don't really need to worry about what this is for (Hint: IT's to do with the Java runetime your phone uses to run apps), all you need to know is that apps use it to store data, which also eats up internal phone memory. Apps2SD+ moves davlik cache to the ext partition on your SD card as well, freeing up even more space. Some people believe that this may come at the cost of performance, as the internal NAND memory should be faster than your SD card (Which is why you also get people arguing over which "class" SD card is better for Apps2SD - the logic being that a faster SD card means less impact from this move), but the truth of the matter is that your applications will be running from your Phone's RAM anyway, so performance isn't really impacted at all. Since most apps are only a few hundred Kb's in size, or a couple of MB at the most, it's a non-issue.
Finally, any recent version of Apps2SD/Apps2SD+ should work with an SD card that is or isn't formatted with an ext partition. It'll check for this partition when your phone first boots and if it's not there, just use internal phone storage.
Having an ext partition WITHOUT Apps2SD+ shouldn't cause any issues, either, so you can format your SD card whenever you're ready.
So in summary:
Apps2SD "fakes" your phone's internal memory and puts it all on a hidden section of your SD card.
Apps2SD+ pushes even more content to the SD card, freeing up even more space on the phone itself.
"Froyo" Apps2SD has various limitations that "old" apps2SD does not, but is much easier to handle as it doesn't involve any kind of "partitioning".
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first, please consider the wording "app2sd+" used above can also be applied to "data2sd+" which should be the main purpose of this thread, because they are similar as they both use the sd-ext partition to store things. the only different is that app2sd+ only moves /data/app and dalvik cache but data2sd+ moves the entire /data partition
now based on my experience of how did i solve my bootloop problems even i install over 300 apps, is, not to integrate Froyo app2sd and app2sd+(or your data2sd+) then things will be fine.
as ive seen that voyager you have "moved all apps to sd" with froyo app2sd while you are TOGETHER using the script of app2sd+(or data2sd+). from the above explanation, your apps and data are now SHARED among /sd-ext and /sdcard/.android_secure which MAY lead to problems on our phones when it enters the process system after going through the bootanimation.
still remember the days and things we have discussed? it was in november when we first known each other i think my founding still applies to data2sd+
voyager20021 said:
For bootloops on Miks CM7 fist post he says
If you get bootloop or stuck at LG logo do next:
Sometimes Recovery can't format /system so you need to clear /system manually. You can do it with this zip (flash as always in recovery), or in mounts menu (clockworkmod recovery only), or with adb:
1. Mount /system in recovery.
2. adb shell rm -rf /system/*
You get 1 error. This is ok.
Will update if I found this bug.
Anyone tried that zip or adb fix? I am not so familiar with adb shell. The zip i think is incompatible or smth.
Franco, do you know if this has something to do with random reboots caused by moving too many apps to sd?
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Miasmic said:
me.
that successfully wiped system partition and 2 months ago i did full wipe (including /system) and reinstall everything then do the same thing, and i got the same results - bootloop
please go to darktremor's main thread (nexus one dev forum) and scroll a few pages back, ive been yelling there for help and they did a lot to help me especially temasek(u know who? a famous n1 developer)....
but finally we got no conclusions trying everything, even switching to s2e had ****ed up my phone.
what solution i can tell is that
fk kernel + mik + dt a2sd script 2.7.5.2-1
+ apps staying on /EXT (shown "on phone")
= no problems
fk kernel + mik + dt a2sd script 2.7.5.2-1
+ apps staying partly on /EXT and partly on /android.secure (shown "on SD card")
= after booting (seen lockscreen) for about 3mins, the phone goes back to bootanimation and boot again
[im sure voyager is asking about this]
p.s. fk kernel + mik + dt 2.7.5.3 beta4
will result in LG logo stuck every 2 reboots. wipe /system no help.
hope my info is useful and yeah, take alook at the dt thread
until now the only solution is not to move apps partly to /android.secure
Sent from my LG-P500 using XDA Premium App
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franciscofranco said:
Why move apps to sd card instead of /ext? doesn't make any sense............. No wonder **** happens...
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Miasmic said:
Yea I agree with your point, moving the app only to /ext is apparently a safer method than dividing it into /ext and /android.secure
But however this method (using darktremor together with froyos a2sd feature) can save even more internal storage on our phones because darktremor doesn't move 100% of the "app" to /ext. Except "app data" , a small portion of "app" is also occupying the internal storage when using dartremor.
Say angry birds, despite its ~500kb /data size, when using darktremor, 18mb its "app" is moved to /ext while 2mb of it is staying in the internal storage. When using froyos a2sd feature, this 2mb is moved to /android.secure therefore even more internal space is free-ed.
According to the main darktremor thread, a user named bassmadrigal and even temasek himself, has stated that integrating darktremor "move to EXT" and froyos "move to FAT" does not produce any problems (at least on their nexus one) and can save even more space.
Well its not a problem for me as I only move 4 of my biggest apps to FAT and not having issues now.
I think voyagers attempting to move a lot of his apps (partly as they still partly stay at /ext) to /android.secure (as I tried before) and he got ****ed up like me before.
Hmmph I am not quite sure, voyager have you tried the same procedure (restore titanium and move them to FAT) without flashing Franco.kernel and only with the ROM (ans default kernel) and darktremor script installed? In that way we can see whether the "issue"(not at all but just an disadvantage of not supporting a feature) is about Franco's kernel or about our phones. cheers!!
Sent from my LG-P500 using XDA Premium App
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franciscofranco said:
Just don't mess with the part that stays in the phone, if you do you're on your own, it's just too damn obvious to waste my time with it, sorry :/
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Miasmic said:
yea, i definitely dont think it is of any priorities to request you to dig on this stuff and please dont, lol
was just telling my experiences to others and esp. voyager
Sent from my LG-P500 using XDA Premium App
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yea, franco also said we shouldn't use the froyo app2sd function when we have already moved stuffs to the /sd-ext using app2sd+/data2sd+
therefore to prevent such abnormal behaviours on our phones we should treat our phones as Android 2.1 or before which does not have the capabilities to use froyo app2sd function to move things to /sdcard/.android_secure instead we should just let them be moved to the /ext partition.
i can confirm that yes there will still be decrease in internal storage because even you got data2sd+, there are something that cannot be moved from the internal storage to /sd-ext and we dont know what. JUST be fuxking sure that all your apps are stayed in "internal storage" (thats a way to fake the phone! you know) and they will be very safe in /sd-ext.
you may also like to install app2sd app but reverse the original concept of this app, i.e. to confirm NO APPS ARE EXISTING IN THE 2nd TAB (ON "SD CARD" with froyo function)
so, to test this out quickly, you may simply:
make proper partitions
wipe properly
flash rom
flash your a2sd+/data2sd+ script
boot phone
run the proper commands (for dt now i would dl a2sdgui and apply stuffs and let it reboot)
now restore titanium backup with INSTALL LOCATION set as "internal storage"
(in CM7 settings > application you may also choose "internal storage" to make sure everything is PURELY moved to /sd-ext instead of sharing among /sdcard/.android_secure with the froyo a2sd function) (however what i can tell you that this CM7 function is not working properly at least with my DT a2sd+ script therefore we have to double check whether it is in "INTERNAL STORAGE" when we install a new app) so now app2sd app came in handy remember is to reverse all apps to internal but not move them to so-called sd which was the original purpose of this app.
ok hope you understand what i meant and now you should not have bootloops
Under the hood​
however, some users have reported that they have NO problems at all when they share their apps among /sd-ext and /sdcard/.android_secure. an example was bassmadrigal (located in the darktremor official thread)
maybe, it is phone specific. maybe, they have shared a less amount of apps as i myself can also confirm that the bootloop problems only occur if we SHARE A CERTAIN AMOUNT OF APPS among the two places.
and for your safety, at least to first eliminate the bootloops problems before doing any experiments, still follow the above and MOVE ALL OF THEM TO so-called "INTERNAL" (pure /sd-ext)

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so you mean to say that keep all the apps in internal memeory and it will be safe in sd-ext with any a2d script rather than moving into sdcard?
There is one script i am tryingvhttp://forum.xda-developers.com/showthread.php?t=1342387. I dont have any script installed.But it is still giving me bootloops.

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williamcharles said:
so you mean to say that keep all the apps in internal memeory and it will be safe in sd-ext with any a2d script rather than moving into sdcard?
There is one script i am tryingvhttp://forum.xda-developers.com/showthread.php?t=1342387. I dont have any script installed.But it is still giving me bootloops.
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yes, the message i would like to bring is rather simple and easy but most of the users are confused about "move to ext" and "move to FAT" and the BUTTON in the application manager of our phones show "MOVE TO SD" which is moving PART of the app to SD-FAT (android.secure) so they are now SHARED and will produce PROBLEMS.
This important point is what most of the script developers have forgotten to warn their users.
Remember to check your settings and ROM/kernels/partitions/scripts compatibility with each other before regarding the script solely as the cause of any problematic behaviour (best way to prove is to see whether there are someone using the same combination without problems
then, install the script, and start installing apps only into "internal storage" (to fake your phone as they actually goes to /sd-ext) and NEVER EVER touch the button "Move to SD" in the application manager then you should be fine as said in my first post, double check they are in the internal storage after you have grabbed a new app from market it will be fine to move it back to "internal storage" as long as you havnt reboot the phone.

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Miasmic said:
yes, the message i would like to bring is rather simple and easy but most of the users are confused about "move to ext" and "move to FAT" and the BUTTON in the application manager of our phones show "MOVE TO SD" which is moving PART of the app to SD-FAT (android.secure) so they are now SHARED and will produce PROBLEMS.
This important point is what most of the script developers have forgotten to warn their users.
Remember to check your settings and ROM/kernels/partitions/scripts compatibility with each other before regarding the script solely as the cause of any problematic behaviour (best way to prove is to see whether there are someone using the same combination without problems
then, install the script, and start installing apps only into "internal storage" (to fake your phone as they actually goes to /sd-ext) and NEVER EVER touch the button "Move to SD" in the application manager then you should be fine as said in my first post, double check they are in the internal storage after you have grabbed a new app from market it will be fine to move it back to "internal storage" as long as you havnt reboot the phone.
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Miasmic said:
yes, the message i would like to bring is rather simple and easy but most of the users are confused about "move to ext" and "move to FAT" and the BUTTON in the application manager of our phones show "MOVE TO SD" which is moving PART of the app to SD-FAT (android.secure) so they are now SHARED and will produce PROBLEMS.
This important point is what most of the script developers have forgotten to warn their users.
Remember to check your settings and ROM/kernels/partitions/scripts compatibility with each other before regarding the script solely as the cause of any problematic behaviour (best way to prove is to see whether there are someone using the same combination without problems
then, install the script, and start installing apps only into "internal storage" (to fake your phone as they actually goes to /sd-ext) and NEVER EVER touch the button "Move to SD" in the application manager then you should be fine as said in my first post, double check they are in the internal storage after you have grabbed a new app from market it will be fine to move it back to "internal storage" as long as you havnt reboot the phone.
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Much simpler explained. We'll have to test your theory. Only now i use ungaze's script which is something like "everything2sd". The button reading move to sd or move to internal has no influence at all. And still having bootloops at some point. Only now the sd ext is 2Gb max, though it never got to fill it without that damn bootloop.
Thanks again MIASMIC for addressing one of the biggest remaining problems which keep us away from having a PERFECT AND COMPLETE O1, now when we are close to having the stable official CM7 and official or not CM9 which will bring so many and awsome STABLE ROMs based on those 2.