[AT&T Samsung Galaxy S II Skyrocket SGH-I727] tjxboy:
Hi guys,

I have a i727 skyrocket use in Germany. (unlock phone)

The network provider is Vodafone.de.

The phone works fine if you only use it in 2G network both call and data. (stock rom by using *#2263# or *#*#4636#*#*, CM9 rom by select 2g only, or *#*#4636#*#*)

But when I turn it to 3g network, problem happened. (both in WCDMA only or WCDMA preferred)

It appears like, when you power on/restart the phone, at first you can see 4G (stock) or H+/H/3G (CM9) icon and the data arrows flash. At this period you can make calls or browse website. But after maybe 30 seconds or 1 minute, when 4G or H icon gets stable. Then you can’t make calls out and if you use another phone to call it, the voice tells you the number you called can not be connected. And also the data was stopped; the browse shows network problem/times out or the same kinds of notice.

Then I use “GSM Signal Monitoring”, try to find out some regular patterns. I found when the signal switch from one base station to another, at first the phone functions is ok, and later when the signal is stable, the phone dead, and maybe several minutes after, when the phone switch to another station, the phone function works again, then about 30 seconds later, dead again. But in all this periods the signal is quite good. (around -60~-80 dBm)

At first I think maybe is the problem about RADIO.

So I try to flash many different RADIOs (T989, T989D, I727R, I757M, I9210, I9210T, E120K, E120S both from stock 2.3 or 4.0 and both with or without RIP), but they all didn’t solve the problem.

And also I try different ROMs (stock 2.3, 4.0; I727R 2.3, 4.0; T989 4.0, CM9; CM10), and the combination with the radios above, but still didn’t work.

Then I noticed some threads about the fast dormancy, I have tried to turn the fast dormancy off or on. But still didn’t work.

Also I noticed about different 3G data forms (HSPA+, HSUPA, HSDPA, UTMS), then I used *#301279# on stock rom to fix the 3g data form in only one kind or only use UTMS, but still didn’t work.

And later I found it is not about the data connection, it is only about the 3G network no matter about the data is on or off, when you switched to WCDMA, then, when the signal stable, you can’t make calls out or receive calls in, and even the signal bar seems great from the begin to the end.Another thing is if you making a call at the first “alive” period, then before you hang up the phone, it all works. Also if you use some online radio software keep the data flow, and the phone will not “dead”, only when the phone is idle, and later after sometime, the signal “dead”.

And the SIM card works fine in other phones in 3G network.

I have tried this in my home and office. In the office the signal always switched to different stations, so it looks a little better. But at home, the signal always stays in one or two stations, so it much easier to see when signal stable, the phone dead.

This problem confused me already 1 month, I tried everything I found and everything I can image. But everything didn’t work. At this moment, I only can use it under 2G networks.:crying::crying::crying:

I am sorry about my English; I try to explain these clearly.

Really hope someone can help me.