Friday, November 16, 2012

本当にドコモのベースバンド(radio.img)で上書きする必要はあるのか?

Editors Note: See below for English.

ドコモ版Galaxy Nexus(SC-04D)がJB4.1にアップデートされたタイミングで手元のデバイスをJB 4.2 (JOP40C)にアップデートしました。

Factory Images "takju" for Galaxy Nexus "maguro" (GSM/HSPA+) (with Google Wallet)

このROMに含まれていたradio.imgのベースバンドはi9250XXLH1で、いつもはflash_all.shでアップデートすることはなくベースバンドはドコモバージョンを残しておくか上書きするのですが、今回はせっかくなのでグローバル版のベースバンドとドコモ版のベースバンドの通信状況を比較してみました。

試しに焼いてみたのは下記radio.img。
  • 2012.06.10: SC04DOMLE3 radio.
  • 2012.11.13: JRO03C.SC04DOMLK2 build. (yakjusc, ドコモ版)
  • 2012.11.13: i9250XXLH1 radio. (takju, アメリカ版, 下のスクリーンショット)
これらを各々インストールした後、通信状況やスピードなどをドコモのFOMA SIMで試してみたのですが、有意な差はありませんでした。(n=2)
なので結論からいうと、気にせず最新のブートローダやradio.imgを焼いても問題がなさそうです。これで迷うことなくROM焼きができますね。





Comparing Galaxy Nexus radio (baseband) between docomo vs global


I have 2 Samsung Galaxy Nexus handsets, and I compared the radio baseband version of those two after updating on the same day. I always leave the docomo radio because I assumed the baseband that the carrier releases includes better support for local radio frequencies or optimized for bandwidth / speed / packet size.

But after comparing, I couldn't find a significant difference between the following basebands:
  •  2012.06.10: SC04DOMLE3 radio.
  •  2012.11.13: JRO03C.SC04DOMLK2 build. (yakjusc, docomo version)
  •  2012.11.13: i9250XXLH1 radio. (takju, US version, screenshot above)
Conclusion :  Flash newer img bundle with stock Google factory ROM.

16 comments:

  1. What's that app that's used in the image?

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  2. Hi all. I;m unsure where i can ask this. and hope you can help me. I'm currently visiting family in japan and considering getting a new plan in docomo with a galaxy note 2 LTE and take it back to australia. would this work? i have telstra back in australia. would the note 2 from docomo be sim locked? and if so. can it be DIy unlocked or are there any available unlockers online? thanks in advance and sorry for posting this here :-/

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  3. telstra? I guess it works after SIM unlocking in docomo shop. Just ask staff to SIM unlock when you buy it, it's 3,150 JPY. (but please be sure you it's docomo carrier version, it has plenty of docomo useless apps)

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  4. This one.
    https://play.google.com/store/apps/details?id=de.android.telnet

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  5. Hi. Anyone knows if the google stock rom is still compatible with FOMAプラスエリア(W-CDMA800MHz)? Japanese devs/bloggers tend to say no, even without a clear proof of that.

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  6. Of course. Who says it's not compatible?

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  7. Lots of people who for this very reason backup and include the docomo radio.img and not the google one in custom roms. I know because I am serching a lot this topic as it's the last thing keeping me from putting a 4.2 stock on a docomo gnex.

    I wonder if there is a way to force the phone to test the 800mhz band in Tokyo

    some links

    - http://androidlover.net/smartphone/galaxynexus/sc-04d-radio-img-backup.html "radio.imgがないと、ドコモのFOMAプラスエリアで電波をつかまなくなる可能性が高いので、今回のバックアップ作業は必須です。"

    - http://lifescape.seesaa.net/article/281532952.html "ドコモ版radio.imgの導入

     radio.imgは国や業者によって異なる利用可能周波数帯を定義するファイルになります。さきほどの国際版ROM導入手順の中で、不要なトラブルを避けるため国際版ROMに付属するradio.img「radio-maguro-i9250xxla02.img」を一旦焼いているのですが、このままではNTTドコモが提供する「FOMAプラスエリア」の電波を拾えないため場所によっては繋がりにくい状態となってしまっていますのでradio.imgのみNTTドコモ仕様のものに戻しておきます。"

    - http://ameblo.jp/xxx-lalala/entry-11101645910.html "また、radio.imgのbackupが必要です。このdocomo用のradio.imgが無いとFOMAプラスエリアの電波を拾わないようです。"

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  8. Those are talking about the radio, not the ROM. Not all ROMs include new basebands. I thought your question was would the stock ROM be incompatible. The answer is no. There is no "stock" radio it differs for every market. Here is the list of the known radios

    http://forum.xda-developers.com/showpost.php?p=20569003&postcount=2

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  9. Yes I was talking about the radio: I just put a stock TAKJU 4.2 factory image from google site (baseband XXLH1) on a docomo galaxy nexus and was wondering if it still capable of using its 800mhz band like before, not worrying about the mountains but signal strength inside buildings, ecc.

    Can you please confirm it can now only use 2100 band like good old nexus one? thanks

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  10. >電波をつかまなくなる可能性が高いので = "There is a possibility"
    >電波を拾わないようです。= "I heard".
    I'd believed the global ROM can't grab 800MHz too. But I found out nobody test it by 2 devices at the same time.

    Also this guy has checked in mountain where edge of plus area by stock radio. http://pocketgames.jp/blog/?p=20185

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  11. Yes, no one of them provides a clear proof. Only the UK galaxy Nexus guy provides evidence, so maybe its okay with 800mhz with google stock image and radio

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  12. Ya, I have N1 too. Confirmed already. And all GT-i9250 hardware is same. (Do you think docomo version uses different radio chipset?)

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  13. confirmed that stock 4.2 radio works with foma plus area or that it doesn't? just to make sure i got it, thanks

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  14. It does, but as you might know, there is no way to determine which band the device is using.

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  15. JB + GN only works HSDPA:8. Stock radio works with foma plus.
    Case closed.

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  16. Have you tried "ro.ril.enable.dcm.feature=1" on build prop?

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