UART Output/ Bootloader hacking/ Kernel Debugging on AT&T SGS2

AdamOutler

AdamOutler

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Feb 18, 2011
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Oct 26, 2011 at 4:17 AM
Technically the GalaxyNexus has a dual core application processor.. however physically its a quad core. Two of the cores are lower power m class processors and dedicated to handle remedial tasks. This is the device which ICS is designed for. I'm not touting anything. I'm defending my decision not to purchase a sgs2. We all make our decisions on our devices based on one thing or another. Ill probly hold off for the galaxy s3 which is to be released in a few months if I don't get a nexus. I'm a big fan of Samsung. They make cutting edge stuff.

Can anyone get pictures of the xOM resistors on the i777 board? I could use them to establish the pattern on Exynos.

I see only 4 movable resistors which i have derermined are likely the xOMs. I was expecting 5 total. Two are located on the other side of the processor for a total of 7 xOMs. I need to see what the xOM layout on the i777 before beginning xOM mods for Exynos.

This device may be more difficult than others as we don't have OM values for boot modes. The development boards may reveal something in this respect as Samsung has a private Exynos manual which I still have not seen.

We could use some pictures to help establish a foundation for boot mode modification and UBM.
 
jake

jake

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Sep 29, 2011
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Dec 8, 2011 at 7:01 AM
AdamOutler said:
Technically the GalaxyNexus has a dual core application processor.. however physically its a quad core. Two of the cores are lower power m class processors and dedicated to handle remedial tasks. This is the device which ICS is designed for. I'm not touting anything. I'm defending my decision not to purchase a sgs2. We all make our decisions on our devices based on one thing or another. Ill probly hold off for the galaxy s3 which is to be released in a few months if I don't get a nexus. I'm a big fan of Samsung. They make cutting edge stuff.

Can anyone get pictures of the xOM resistors on the i777 board? I could use them to establish the pattern on Exynos.

I see only 4 movable resistors which i have derermined are likely the xOMs. I was expecting 5 total. Two are located on the other side of the processor for a total of 7 xOMs. I need to see what the xOM layout on the i777 before beginning xOM mods for Exynos.

This device may be more difficult than others as we don't have OM values for boot modes. The development boards may reveal something in this respect as Samsung has a private Exynos manual which I still have not seen.

We could use some pictures to help establish a foundation for boot mode modification and UBM.
Click to expand...
My fault fellas I stand derped lol.

Cheers!

*edit*

sent via ICScrewed sans Entropy's DD
 
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jbradt

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Mar 16, 2008
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Dec 8, 2011 at 11:54 AM
Amplified said:
Roflies... even though it was 10/25... how does this benefit development of the sgh-i777? Wrong thread? Perhaps a "tech spec speculation forum?)

sent via ICScrewed sans Entropy's DD
Click to expand...
Just wondering if you've read the entire thread before posting this...?


Sent from my SAMSUNG-SGH-I777 using XDA App
 
gr8hairy1

gr8hairy1

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Jan 15, 2012 at 6:39 AM
Sweet. Just got done doing the unbrickable mod to two captivates. Painfully small soldering, but huge pay off in having a phone that can never ever be ruined. That's pretty awesome.

Sent from my páhhōniē
 
gr8hairy1

gr8hairy1

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Jan 18, 2012 at 2:35 AM
Well adamoutler won the i777 and the asus transformer! Here's to really hoping the unbrickable mod comes to both!

He just now needs to have a sgsii sent to him. Here's a post from the focus s forum:

AdamOutler said:
So I won the XDA phone of the year contest. I showed my work on the Galaxy S 2 and I was voted to win a AT&T Galaxy S 2 http://www.xda-developers.com/announcements/xdas-favorite-phone-and-tablet-of-2011-contest-vote-now/

I am typing this on a Focus S i received from someone at Samsung. This is not what I was expecting. My initial impressions:

1. Laggy. When loading a page, the device tends to lock up and words become illegible.
2. No status indicators when browsing the internet.. I want to see time and signal strength when I post a new thread.
3. Copy and paste should not be the default when you select a cursor position
4. Autocorrect seems to be pretty darn good.
5. Its pretty.

I really hope I'm not stuck working with this closed source device. Everything about it is closed source, down to the Qualcomm processor. As a hobbiest, this device isn't valuable. It is a finished product without the ability to be modified or changed in the true xda hardware/kernel hacking manner.


I'm sorry if I offend anyone. This is not my intent. This device is definitely not for me.
Click to expand...
Sent from my páhhōniē
 
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AdamOutler

AdamOutler

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Jan 25, 2012 at 9:25 PM
Actually, if anyone wants to help, look at the video...

On the resistor to the right of the "XOM4" resistor which i've labeled. Both sides of this resistor on my device are shorted to ground. I believe this resistor is "XOM6", and the resistor required to boot from USB. This seems to be a problem with my board.

There should be resistance, however it seems that my board was drawn with a bad trace. If someone could take the time to verify this resistor with a multimeter set for ohms, it would help.

If someone could measure from one side to the other, it would be very helpful for this project.
 
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Red5

Guest
Jan 25, 2012 at 9:37 PM
AdamOutler said:
Actually, if anyone wants to help, look at the video...

On the resistor to the right of the "XOM4" resistor which i've labeled. Both sides of this resistor on my device are shorted to ground. I believe this resistor is "XOM6", and the resistor required to boot from USB. This seems to be a problem with my board.

There should be resistance, however it seems that my board was drawn with a bad trace. If someone could take the time to verify this resistor with a multimeter set for ohms, it would help.

If someone could measure from one side to the other, it would be very helpful for this project.
Click to expand...
So the AT&T phone that XDA gave you is defective?
 
B

Benjamin Dobell

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Jan 26, 2012 at 2:46 PM
Adam, I disassembled my brand new Galaxy S II as a bit of a test run. I can't tell from the video exactly where the resistor is that you require checked. If you can upload one or two images that indicate where it is and how to get to it then I'll try again tomorrow.

Word of warning for people disassembling their Galaxy S II. It might be different on the i777, however for the GT-I9100(T) at least, the plastic surrounding the headphone jack is EXTREMELY thin on one side. Be careful not to crack it like I did!
 
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AdamOutler

AdamOutler

Retired Senior Recognized Developer
Feb 18, 2011
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Jan 26, 2012 at 9:45 PM
Here's where we are at.

XOM1, XOM2 and XOM3 are designed to be "switched" from the top position to the bottom. Switching these resistors fails boot sequence and forces boot from USB, however the device will not boot normally. The device will attempt to boot from SDCard or from other unsupported methods. This is not ideal as using these will require an external switch to be mounted for use during recovery.

We want to find the XOM which switches the boot sequence from "normal", UART, USB to UART, USB, "Normal".

Because the development board for Exynos4210 shows the XOM0 and XOM7 hardwired... And because other CORTEX A9 devices (like OMAP4) use SYS_BOOT_6 and SYS_BOOT_7 to control internal/external clocks...... I believe the XOM we are after is XOM6.


In the following picture I've annotated the XOMs I've been able to locate. The layout on the international GS2 (i9100) is the same as the layout on the AT&T GS2 (i777). These are practically the same board with minor revisions.

On my I777, there is a resistor shorted. Both leads are reading the same potential and have a dead short between them.

This picture has a couple of errors. XOM0 is irrelevant. The rest are spelling and gramar errors

Benjamin, or anyone else, please verify this. I need readings from an i9100 and an i777 before I remove the resistor and start cutting traces on my board.

Please test the one I marked as shorted on both sides and the ones next to it which are unmarked. I am asking for a power-off resistance reading between ground, side 1, side 2 and across the resistor. if shorted ,they will read less than 2 ohms.
 
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