iPhone iCloud and locationd 100% CPU on old-bootrom 3GS 6.1.3

Just a quick heads-up to 3GS users with old-bootrom and running 6.1.3 as they may probably run into the same problem:

My iPhone has shown the typical signs of something's using the CPU all the time, draining the battery very fast and making the phone both warm and sluggish. The great tool “Top” I've previously recommended previously too in several threads here has shown the following:



As you can see, it was “locationd” that has continuously used the 100%.

I've quickly found out that it wasn't any location service or automatic time update service (all disable-able from Settings – disabled them all for test) that forced it to continuously use the CPU. Neither did any jailbreak tweak (tested this by just running Cydia, which disables most JB tweaks). After a while, I've found out it was iCloud. After a disable in Settings (with deleting local synchronized stuff) and re-enable it with all the features (including Where's my Phone), the problem was gone.

During all this time, continuously watching the results returned by top was of great help. I could immediately see the effects of dis/enabling a certain, location-specific feature of iOS, third-party apps or JB tweaks. Without this, it would probably have taken days to find out it was iCloud that caused the problems.

kalirob99 said:

Interesting, I'm having a similar issue with my 3GS. So after deleting the iCloud settings, you reentered it and it was fine?

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Yup - now, it's working just fine. Before that, not even hard resets helped.

Are you also having 100% CPU usage problems with the same "locationd" daemon?

kalirob99 said:

Yeah, I saw it in Top. What were the step by steps you went through? Might as well detail for all us with 3GS's on iOS 6.

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1, You mean installing top and accessing / running it, or, just disabling / re-enabling iCloud?

2, so, you had exactly the same problem? I might restore my 3GS to see whether the bug is also present on non-JB'n devices and if not, when it starts showing up after JB'ing.

kalirob99 said:

Yeah, #1, and I'm seeing the same issue. :/ The drain is crazy, I'm interested to also hear if you see the issue unjailbroken, but don't risk the jb if you don't have to.

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Thanks. I'll restore today to find the culprit. Will report back.

kalirob99 said:

Looking forward to hearing what you find. Good luck.

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Restored my 3GS and started testing.

<edit: nvm. Will update soon.>

Menneisyys2 said:

Restored my 3GS and started testing.

<edit: nvm. Will update soon.>

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Yes, it IS an iOS bug and not because of JB'ing. I've done some serious tests, restoring the 3GS three times and I've found out the following:

- if you, during setting up the phone for the first time, provide it with an iTunes login / password, it'll most probably be stuck at 100% CPU usage. After an iCloud deactivation (with deletion) and reactivation by entering the iCloud account data again (and a reset), this problem will go away.

- if you refuse to give an ID at setup time, that is, you tap the "Skip this step" link in the lower right corner and, then, tap the "Skip" button in the following dialog:



it won't have 100% CPU time, not even when (later) you do activate iCloud.

kalirob99 said:

Wow, so it's all about the initial iCloud set up. I did enter it right off on restore. :/
I logged out of iCloud, and the battery still seems quick to drain, but no where near as bad. It wasn't this bad prior to installing 6.1.2, so ill just do a restore.
I was wondering your thoughts on upgrading the 3GS to 6.1.3? Since its one of the first 3GS', I take it I could still jailbreak it?

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When did you buy it? If it is lower than around week 35, your bootrom is old. Then, you can absolutely safely upgrade. Mine is week 29 (I've lined up for hours on the first day it arrived here in Europe; hence, I have one of the earliest units) and have untethered 6.1.3 JB.

See http://www.imore.com/daily-tip-iphone-3gs-older-newer-bootrom on finding out the week number.

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kalirob99 said:

Wow, so it's all about the initial iCloud set up. I did enter it right off on restore. :/

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No problem - just log off, let it delete synched stuff, log on again and reset. There won't be any problem after resetting.

I logged out of iCloud, and the battery still seems quick to drain, but no where near as bad.

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See above - you might have forgotten to hard reset.

kalirob99 said:

I have an MB Model, so it's old boot rom. Do I need a specific version of redsn0w? And alright I'll try the steps again tomorrow to stop the leak, thanks!

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Official version will do.

kalirob99 said:

Thanks, I plan on updating later today and ensure I SKIP the iCloud login when I start up 6.1.3 lol.
I figure 6.1.3 fixes something as most new iOS versions do?

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Dunno - I only use my 3gs occasionally (mostly for teaching / development / article writing and in no way for phoning, time-killer gaming, Web browsing etc. That is, I generally don't use all its features and/or don't run into other bugs only discoverable via, say, playing.)

kalirob99 said:

Same here, it's for the gym and iMessage use when my phones charging. Is yours 6.1.3?

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Yup, 6.1.3