1. Alree

    OP Alree GBAtemp Regular
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    AFAIK, everytime a, event is released in ACNH, banned/offline players need a Dumped BCAT.
    As we know, some time it's a pain to install it.

    btw, it seems that all BCAT stuck to some rules.
    JSON like files, and a files "files.meta" who list them all.

    JSON Files are easy to read.

    ex:
    [​IMG]

    Files.meta contain this.

    upload_2020-5-7_11-19-58.png

    Actually there is two solution.
    - Patch game executable to NOP/JZ/JMP the BCAT test every time. (Not user friendly)
    - Forge BCAT, to be able to play every event without depending on a third party to dump BCAT

    We already know that:
    BCAT_EventFlag_000 = Easter Egg Event
    BCAT_EventFlag_001 = 1st May ( May Day Tour)
    BCAT_EventFlag_002 = International Museum Day
    BCAT_EventFlag_003 = June Wedding Opening Event
    BCAT_EventFlag_004 = Weeding Seasons

    Every help accepted =)
     
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  2. burhansalih

    burhansalih GBAtemp Regular
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    Would be good if there was an easy way for banned switches to install these :)
     
  3. Oracleofire

    Oracleofire Advanced Member
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    It's apparently trivial, according to SciresM.

    [​IMG]
     
  4. Alree

    OP Alree GBAtemp Regular
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    I saw that and even replied
    But it doesn't say if it bypasses the BCAT test or if it creates the BCAT manually.
    Assuming that it bypass TEST (what i call the Not User Friendly solution)
    I already bypassed some check to leak MayDay maze but it's a pain to keep this way open at every patch.
    I look for another way which will allow why not the creation of homebrew and share knowledge.
     
  5. SethPDA

    SethPDA Member
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    What do you mean by that?
     
  6. Alree

    OP Alree GBAtemp Regular
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    by what ?
     
  7. Alree

    OP Alree GBAtemp Regular
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    Actually I'm able to create and inject fully functional Forged BCAT.
    Now, I wonder how can we "spoof" Nintendo service trough DNS to inject them on a "non hacked" switch. Any idea ?

    [​IMG]

    Have already do the whole upcoming event,
    https://twitter.com/iAlree/status/1265240009587687424

    but want to "enable" it event on Legit switch for testing purpose
     
  8. Mahesh

    Mahesh Advanced Member
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    can you just update via local? it's one of the update versions to match, if the hacked is on d, maybe the legit one goes to it
     
  9. Alree

    OP Alree GBAtemp Regular
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    no.. game version work this way, not BCAT.
    Those flag need at least a faked connection to Nintendo Servers. That's why we inject them on banned switch
     
  10. silvershadow

    silvershadow GBAtemp Regular
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    just adding some information to make sure you didnt miss anything:

    i noticed on museum day, everyone used a bcat to get them to 1.2.0b, but when i installed the bcat here, i had 1.2.0c. and museum day worked as expected. i did not time travel to the next event though.

    https://github.com/agronomru/ACNH-BCATs/releases

    i believe that is a dump from official but i could be wrong.

    so in ur other post, you shared 1.2.0c and 1.2.0d that u forged (but i havent had a chance to compare the 1.2.0c from that github with your 1.2.0c).

    hopefully this info will hopefully help with testing and theory crafting for future bcats.
     
  11. purechaos996

    purechaos996 GBAtemp Advanced Fan
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    Interesting. Have you documented the process on what you edited/forged. I'm surprised to see the items for all the events are in the game already, I would have guessed Nintendo would be locking those behind updates as well.
     
  12. Alree

    OP Alree GBAtemp Regular
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    Well in fact BCAT are really easy to make.
    Here what we have, and how you can create a BCAT.

    First BCAT was like this:

    Code:
    {
    "mFlagVer": 1,
    "mRegion": "JP,AU,KHT,CN"
    "mFlagId": 0,
    "mFlagName": "BCAT_EventFlag_000",
    "mStartDateTime": "1999-12-31T00:00:00",
    "mEndDateTime": "2061-01-01T23:59:59",
    "mIsUseNetworkTime": false,
    "mIsUseNetworkTimeZone": false
    }
    This was the first ever version of BCAT for ACNH, and this one is "region locked". So you will find 3 BCAT for Easter Event on for Oceania/Japan, another for USA, and finally one for Europe
    What changed after that is mostly the version of BCAT.

    MayDay was like this:
    Code:
    {
    "mFlagVer": 2,
    "mFlagId": 1,
    "mFlagName": "BCAT_EventFlag_001",
    "mStartDateTime": "1999-12-31T00:00:00",
    "mEndDateTime": "2061-01-01T23:59:59",
    "mIsUseNetworkTime": false,
    "mIsUseNetworkTimeZone": false
    }
    AS you see, "mFlagVer" increased to "2" and "mFlagId" to "1".
    mFlagVer 2 doesn't need a "region to be specified so go on, we have a pattern

    Museum Day, only change was "mFlagId" increased to 2 and BCAT name changed
    Code:
    {
    "mFlagVer": 2,
    "mFlagId": 2,
    "mFlagName": "BCAT_EventFlag_002",
    "mStartDateTime": "1999-12-31T00:00:00",
    "mEndDateTime": "2061-01-01T23:59:59",
    "mIsUseNetworkTime": false,
    "mIsUseNetworkTimeZone": false
    }
    Wedding ? change was "mFlagId" increased to 3 and BCAT name changed
    Code:
    {
    "mFlagVer": 2,
    "mFlagId": 3,
    "mFlagName": "BCAT_EventFlag_003",
    "mStartDateTime": "1999-12-31T00:00:00",
    "mEndDateTime": "2061-01-01T23:59:59",
    "mIsUseNetworkTime": false,
    "mIsUseNetworkTimeZone": false
    }
    So next step is, how does Switch could validate this files ? ... files.meta
    This file is simple in fact, as already showed:

    [​IMG]

    So what we need to add at the end of this file is information from BACT files..
    FileName .. not really difficult.
    A random key, but it's in fact unused. so whatever you want and you'll see that "forged" BCAT didn't have same number here.
    File Size here always 159 bytes
    And the MD5 Hash of file "BCAT_EventFlag_00x" generated. who is Truncated and reverted..

    Now, how I know there is a 1.2.1D and a 4th BCAT ?

    well every BCAT supported by actual version is in "romfs/Bcsv/EventFlagsLandParam.bcsv"
    when you open it... we have this BCAT 004 mentionned.. and this one trigger the 1.2.1D

    upload_2020-5-27_21-24-23.png


    — Posts automatically merged - Please don't double post! —

    Only real difference is the "Random Key" as I say, this is unused in fact.
    So this is another forged wedding BCAT included in Museum BCAT that's why you have 1.2.1.C
    So we just increased it, but we do not start with the same. That's the difference.
    And this is the only spot where our BCAT could differ from those provided by Nintendo. Cause we don't know what the number is before official BCAT release.

    upload_2020-5-27_21-17-50.png
     
    Last edited by Alree, May 27, 2020
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  13. purechaos996

    purechaos996 GBAtemp Advanced Fan
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    Great explanation, I'm assuming Nintendo is going to update the BCSV file in a future patch for more events. Glad I understand how this all works and where to look in the future. Thanks.
     
  14. Dayfid

    Dayfid GBAtemp Regular
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    I assume they'll also update and actually make use of the "random ID" within the files to verify legit bcat files. So that'll mean either ending forged bcat files for ACNH or they'll be harder to make. : - )
     
  15. Alree

    OP Alree GBAtemp Regular
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    If they do this, they will be be stuck in another problem.
    ANCH is not the only one game who use BCAT flag and BCAT are console wide.
    So this will be part of Fw update.. and I'm still in 9.1.. They cannot force anyone to update console fw

    Btw is still possible to "bypass" integrity check with IPS patch or EDIZON Code.
    And this way should not be blocked. At the end Hacking scene always win

    Nintendo should Know that everything is studied. but they change nothing: https://switchbrew.org/wiki/BCAT_services
     
    Last edited by Alree, May 28, 2020
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  16. Dayfid

    Dayfid GBAtemp Regular
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    Okay, that's good to know and I was hoping there would be a way around it with patches. Wait so the random ID isn't used in ANY game? I thought they were just being stupid and not using it with ACNH.
     
  17. Alree

    OP Alree GBAtemp Regular
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    Even if it was used in future. Switch and Game should have a "backward" compatibility to use BCAT prior to this patch.. so not really an issue. Just some work to know how that's works and relaunch the Cat-Mouse chasing game
     
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  18. Wolfling

    Wolfling GBAtemp Regular
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    is it a ban risk to install a bcat early on an online switch?
    say next bcat comes and its released 5 days early. if i install it is it a huge ban risk?

    — Posts automatically merged - Please don't double post! —

    by this, do you mean, just put anything in the reandom key and itll worK?
     
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