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Wipe and delete data & cache, why exactly?

Discussion in 'Android Devices' started by Lock-N-Load, Aug 5, 2010.

  1. Lock-N-Load

    Lock-N-Load Android Expert
    Thread Starter

    So, this has been plaguing me as I try to understand the logic.

    If you do not root, you could go from 2.0.1 to 2.1 with no wiping of data and cache, it just installs & away you go. Same with 2.1 to 2.2. No wiping of data and cache and all is still there as you left it: apps, settings, preferences, etc.

    SO, why is it important to do this if you root? What's the difference? And, who said it was important to do? Is there some exact proven logic on why if your rooted you must do this and if not, your somehow fine?

    That 1 step difference causes a lot of extra work, so I am wondering why this is said to be a must for rooters and non rooters need not do it when they get updates?

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  2. vincentp

    vincentp Android Expert

    Essentially it's because it can cause compatibility problems when switching ROM's. Some ROM's will include things in the system partition or have certain tweaks and settings. If there are conflicting settings or files left over in the cache or in your data partition, it can create usability or even boot issues.
  3. Lock-N-Load

    Lock-N-Load Android Expert
    Thread Starter

    hmmm... but people that get an update OTA are also "switching roms" - just like a person that forces the switch in a root setting - so still not sure how it is different.

    so I understand what is claimed "can" happen, just still not getting why only root people would have to worry about it when in the end, we are all just switching roms.

    have you actually read many stories of root people going from say 2.0.1 to 2.1 or 2.1 to 2.2 and not doing this and having issues? because people that go OTA do not.
  4. vincentp

    vincentp Android Expert

    Well when they get an OTA update, the file structure, apps etc are all dictated by Motorola so everything plays nicely with the old build. ROM's are all designed by different people and have different apps and features included.
  5. Lock-N-Load

    Lock-N-Load Android Expert
    Thread Starter

    So, if you took Pete's stock rooted Froyo - one not modified or tweaked (FRG01B), only just rooted - why would you not be able to just drop that over a rooted 2.1 just like a person doing 2.2 over 2.1 OTA and NOT have to data and cache wipe?

    it almost seems like your saying if you used an unmodified or tweaked 2.2 ROM that has only been rooted - like FRG01B - then you should be able to install over a basic 2.1 root with no wipe needed. BUT if you want a tweaked 2.2 like BB 0.4 (FRF84B), then you should wipe.

    are we on same page here?
  6. wadsface

    wadsface Member

    In that specific case you are talking about there Lock, you probly would be fine not wiping. The problems occur when you are going from say, CM6RC2 to Chevy's SS. Both built completely different with tools and things in CMRC2 that Chevy's ROM would not replace/delete when his was flashed leaving little bits and pieces of things in there that can cause problems. Some of the time you are fine not wiping but Dev's just advise it because they dont know what another Dev might have put in the ROM you are flashing over that will cause problems.
  7. wadsface

    wadsface Member

    Also, some people just LIKE to wipe to avoid problems from even getting a chance to happen. This is me. I have sufficient back-up options/time to re-setup so it is not a big deal for me.
  8. Lock-N-Load

    Lock-N-Load Android Expert
    Thread Starter

    well, it is like this.. thinking of the path of least resistance.

    if you have a basic Pete's rooted 2.1, then you place over that - WITHOUT wiping - a basic Pete's rooted only 2.2, all your apps and settings and such should be in tact and in place and that is a whole lot less work then also having to go through and replace apps 1 by 1, replace data, check settings, blah blah blah. It just seems so logical. it would be just like a 2.1 to 2.2 OTA. same dev, same basic root, 1 over the other.

    BUT, I can see where, if you want to start cross mixing ROMS from dev's it might make some sense which is why everyone generically says delete and wipe as they all assume your jumping around ROMS so it is a safe general comment to make - but not always necessary in certain cases like my scenario here. But to just take a basic rooted 2.1 to basic rooted 2.2, it seems way overkill and you save all that work to reload apps and settings and data. It then would seem just as logical, having gone from a basic root 2.1 to a basic root 2.2 that once that 2.2 jump is made, from what I read elsewhere, going to another 2.2 by the same dev, like his tricked out BB 0.4 would also not need a wipe and clear since your then just going from Froyo to Froyo by same dev.

    get the theme here? going these 2 vanilla rooted ROM install steps is so much easier and quicker than doing a 2.2 and having to reload apps and settings and data and such. not sure where my logic fails here it at all.
  9. OMJ

    OMJ Bazinga

    Note I did not read this entire thread...

    The updates you get OTA are not entire roms. They are smaller updates. Take the FRG01B update it is the biggest of all the ones we have had on the droid so far and it was 45mb. A rom is generally 65 to 75mb, Roms change the entire /system directory while OTA updates just replace a few files and add a few. The difference is motorola knows what all stock users have in their /system directory. A rom dev has no clue what you have there so they must replace everything. The differences between roms are what ultimately cause issues.
    wadsface likes this.
  10. Lock-N-Load

    Lock-N-Load Android Expert
    Thread Starter

    "The updates you get OTA are not entire roms. They are smaller updates"

    okay, that adds a big piece to this puzzle.

    so simply answer this as it does not require reading everything.. if you have a basic Pete's rooted 2.1 ROM, then you place over that - WITHOUT wiping - a basic Pete's rooted only 2.2 ROM - 2 odexed vanilla ROMS from same dev - all your apps and settings and such should be in tact and in place and that is a whole lot less work then a deodexed 2.2 ROM and restoring files & data. agreed?
  11. wadsface

    wadsface Member

    You are right on the first part and wrong on the second. You can (probably, dont quote me) go from stock rooted 2.1 to stock rooted 2.2 and have not problems. As OMJ said, the OTA updates are not the same as the ROMs so it is not like you are giving yourself a normal 2.1 to 2.2 update, but you are more then likely to be fine. The froyo to froyo thing is wrong because of all the extra things the Devs put into the ROM and the different build versions they use to do it. If you were to have a custom ROM built from source with FRG01B and for some reason flash something else built from FRF84 without wiping you will probly have troubles even though they are both "Froyo"
  12. wadsface

    wadsface Member

    Is that what you are trying to do Lock is go from stock rooted 2.1 to stock rooted 2.2 without wiping?
  13. Lock-N-Load

    Lock-N-Load Android Expert
    Thread Starter

    yeah,.. pretty much :eek:

    though I am not sure if I should be :eek:

    it just seemed to make sense and then get some benefits of 2.2, download a kernel, be able to over clock, and worry about a really tweaked 2.2 later when I have time. however, my question as to why was legit.
  14. Lock-N-Load

    Lock-N-Load Android Expert
    Thread Starter

    well, we are about to find out what happens in this scenario as I am trying it right now

    basic Petes 2.1 to basic petes 2.2 w/ no wipe (but did backup ROM of course) as talked about above .. wish me luck :)

    EDIT: now at 2.2 FRG01B, all data seems intact, nothing odd noticed just yet, didn't have to load any apps or data or settings... will report back if I notice anything odd or kooky.
  15. wadsface

    wadsface Member

    Well grats, I hope it works out for ya!
  16. nstallion

    nstallion Android Expert

    I think it's good to get a few backup applications to save your apps, data, texts etc and just get used to wiping.

    If you don't wipe data and cache, you will not be able to determine if stability issues you are having are caused by a new ROM you are trying out, or just the fact that you didn't wipe.
  17. inssane

    inssane Android Expert

    Different devs include different features. Updates typically add files and don't remove them, so you are stuck with "leftovers" that the current and updated ROM has to deal with now and possibly work around and such.

    ie - a stock 2.1 has the standard, limited feature, phone.apk and settings. CyanMod has many many tweaks in it. Go from CyanMod back to rooted 2.2 for example and the "extras" CyanMod had in it aren't uninstalled, files are just overwritten so there can be numerous compatibility issues.

    Hope this helps
  18. inssane

    inssane Android Expert

    Any update for us?
    It definitely CAN work, as I have tried similar, but as I have also experienced - it can go very bad. I lost the ability to get into recovery for an hour, nor my main OS. Psychotic loops.
    After that I ALWAYS wipe - so in the future, my advice is to simply gather the BU tools you need and wipe every time. Look around - I made a detailed explanation of how to change ROMs with a wipe in an hour.
    If it was really annoying, I wouldn't do it :)
  19. Lock-N-Load

    Lock-N-Load Android Expert
    Thread Starter

    hey.. so far so good. I have no real issues to report.

    I had 1 glitch where I went to do a backup after I have 2.2 all setup in clockworkMD and booted into recovery and clockworkMD was gone/not working. I just flashed SPRecovery intead, did nanodroid backup, came backed and reflashed clockworkMD and viola.. fine. Is this related? hard to say. I say no as I have read/seen/had issues with clockworkMD so I am not going to put it on my update method here.

    so, at this stage, it seems very much doable and stable.

Motorola Droid Forum

The Motorola Droid release date was November 2009. Features and Specs include a 3.7" inch screen, 5MP camera, 256GB RAM, processor, and 1400mAh battery.

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