My iPhone 3Gs auto black screen

I am also having this problem, except with a 1.5-year-old iPhone 4.

My iPhone will randomly shut itself off for no apparent reason. It seems identical to me turning it off. It happens about once a week on average, but on some days it has happened multiple times.

I did a "reset to factory settings and restore", which "fixed" the problem for about 10 days, but now my phone is randomly turning off again.

The specific problem, which I see in the "CrashReporter" logs, is:

> Boot faults: rst vdd_under

You can find ALL the times & dates this has happened by searching for the string "vdd_under" using this command:

grep -A 4 -B 4 vdd_under ~/Library/Logs/CrashReporter/MobileDevice/*/*.log

I am also having this problem, except with a 1.5-year-old iPhone 4.

My iPhone will randomly shut itself off for no apparent reason. It seems identical to me turning it off. It happens about once a week on average, but on some days it has happened multiple times.

I did a "reset to factory settings and restore", which "fixed" the problem for about 10 days, but now my phone is randomly turning off again.

The specific problem, which I see in the "CrashReporter" logs, is:

> Boot faults: rst vdd_under

You can find ALL the times & dates this has happened by searching for the string "vdd_under" using this command:

grep -A 4 -B 4 vdd_under ~/Library/Logs/CrashReporter/MobileDevice/*/*.log