Redmi 3s With Lte B20 800mhz


MarkyO

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Oct 5, 2016
85
18
My international version came with the same baseband as in the previous post and B20 is working. So baseband doesn't help you.
 
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deepknight

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Sep 11, 2016
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My international version came with the same baseband as in the previous post and B20 is working. So baseband doesn't help you.
Thats very interesting. So the Baseband version is not the key... Someone with other ideas how to unlock lte bands or transfer the settings from international phone to non international one ?
 

manzing

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Sep 27, 2016
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20
Thats very interesting. So the Baseband version is not the key... Someone with other ideas how to unlock lte bands or transfer the settings from international phone to non international one ?
If you read in first page of this topic or some threads on XDA dev, it seems that we need to modify some NVRAM values to enable B20 (or other hardware supported bands). Nobody seems to be able to show us it can actually work though. For now.
Some reading : http://forum.xda-developers.com/sitesearch.php?q=redmi unlock band
 

deepknight

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Sep 11, 2016
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If you read in first page of this topic or some threads on XDA dev, it seems that we need to modify some NVRAM values to enable B20 (or other hardware supported bands). Nobody seems to be able to show us it can actually work though. For now.
Some reading : http://forum.xda-developers.com/sitesearch.php?q=redmi unlock band
Yes thats right, but somehow you can backup / restore nvram contents?? How is the nvram programmed, are updates with normal roms included , which we can use ... ? Modify with Qualcom Tools seems to work, but for me the changed settings where not saved.
 

manzing

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Sep 27, 2016
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Yes thats right, but somehow you can backup / restore nvram contents?? How is the nvram programmed, are updates with normal roms included , which we can use ... ? Modify with Qualcom Tools seems to work, but for me the changed settings where not saved.
Have you tried to change and save several times ? On first page shiaido said he had to do it 3 times or more for the changes to be effective.
 

kicksomeazz

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Jan 24, 2016
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15
I tried it and succeeded in saving the 6828 values. BUT: the 6829 values (extension DIV) could not be saved. I tried over and over again. However, B20 is not active, even though the B20 activation at the 6828 value was successful. So either the 6829 value needs to be saved as well (however this could be done) or there has to be another way.

Gesendet von meinem Redmi 3S mit Tapatalk
 

eddiec

Members
Oct 28, 2016
3
15
I tried it and succeeded in saving the 6828 values. BUT: the 6829 values (extension DIV) could not be saved. I tried over and over again. However, B20 is not active, even though the B20 activation at the 6828 value was successful. So either the 6829 value needs to be saved as well (however this could be done) or there has to be another way.

Gesendet von meinem Redmi 3S mit Tapatalk
Like you I couldn't save the extension Div settings for B20 so I edited and saved them with QXDM and then confirmed the B20 band was enabled via quadcomm tool. Still no 4G on 800Mhz required for vodafone UK.

Took quite a bit of time and hassle to find this out given I had to flash the developer rom the hard way. install twrp the hard way
root via twrp then fight with quadcomm tools for some hours before there support told me my version was out of date and wouldn't connect to there servers and yes you do need a login for quadcom tools as it needs this to pull down some extra settings apparently in the background.
then had the hassel of it not working for div extension so ended up fighting with some binary strings to figure out which value was for B20.

End result still no 4G - would have been quicker to have a Hong Kong phone mailed to me. If by chance I'm not actually in a 4G area and do wander into one and this actually did work I will comeback and let you all know the exact steps.
 
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manzing

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Sep 27, 2016
35
20
I tried it and succeeded in saving the 6828 values. BUT: the 6829 values (extension DIV) could not be saved. I tried over and over again. However, B20 is not active, even though the B20 activation at the 6828 value was successful. So either the 6829 value needs to be saved as well (however this could be done) or there has to be another way.
Just did the same thing : First write for 6828 value is effective but unable to write 6829 value with qualcommtool.exe.
When i look for B20 4G network (others operators use it in France, not mine : i try in case i change...) i don't see any.
So it seems the change of NV value had no effect.
Besides, i have read many posts dealing with that problem and it seems that even if the qualcomm chip is actually supporting B20, a compatible antenna needs to be implemented in the phone. Guess it's not the case for China / India model, and as nobody seems to report a working mod, i am afraid we won't be able to unlock this band ever... :(
 
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radmir

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Oct 12, 2016
9
11
Could anyone test this patch? Just flash via TWPR. B20 should be already unlocked in NVRAM.
 

eddiec

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Oct 28, 2016
3
15
Could anyone test this patch? Just flash via TWPR. B20 should be already unlocked in NVRAM.
I'll aim to do this tomorrow once I fit a new screen to the phone I unlocked the B20 on previously. What is the patch designed to do exactly? Or where did it come from. I previously gave up and ordered a Hong Kong version so I have both versions at present but never unlocked xiaomi's lock to play with the Hong Kong version.
 

eddiec

Members
Oct 28, 2016
3
15
Sorry but the patch on to top of B20 NVRAM did not work.

Further to this when replacing the screen on my non B20 working Redmi 3s I found that there appeared to be two additional points for antenna connections. I opened my B20 phone from Hong Kong via ********** and neither of these antenna points are used.

The antenna point on both phones runs a cable down to the charging/speaker/mic circuit board and does not give signal when the circuit board plastic cover is off. Basically the real antenna must be inside the bottom circuit board cover. Swapped the circuit boards and circuit board plastic covers around in different combinations between the two phones but I never achieved a 4G signal on the Chinese non B20 functioning phone which is what I'm trying to achieve for Vodafone 800MHz UK as they only operate 1200MHz in three cities in the UK.

(When I refer to cover above I do not mean the back outside cover but the plastic with the loud speaker moulded into it.)

From comparing the circuitry and lay out I see little difference of make up but the punched tin moulded plastic the type of mesh and part numbers all have some kind of slight difference in make up right down to the colour of pull sticky tape holding the battery in. These two phones have been manufactured in two very different places. Having said that I believe what were looking for is still software/firmware based as i don't see any real hardware difference.
 
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great9

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Mar 10, 2017
8
1
From comparing the circuitry and lay out I see little difference of make up but the punched tin moulded plastic the type of mesh and part numbers all have some kind of slight difference in make up right down to the colour of pull sticky tape holding the battery in. These two phones have been manufactured in two very different places. Having said that I believe what were looking for is still software/firmware based as i don't see any real hardware difference.
Any chance you have photos of the PCBs?
 

MarkyO

Members
Oct 5, 2016
85
18
@eddiec
Did you try to make a QCN backup of your B20 device, change the IMEIs and MAC inside the QCN file and restore it to your non-B20 device? This might do the trick.
 

Kalips

Members
Sep 18, 2016
1
13
I was (theoretically) able to unlock Band 20 with QualcommTool.exe according to the Info on xda-developers.

First put phone in Diag mode: In the shell input as Admin:
adb devices
adb shell
su
setprop sys.usb.config diag,adb

then

-> run QualcommTool.exe as Admin

-> with right mouseclick first activate an then connect the diag-com port

-> click the tab "bands" then the subtab "LTE"

-> (1) "Read" with activated "LTE BC Config #6828" -the one without "DIV" (I had to do it twice till it worked)

-> then click the selected band you want to add

-> (2) write

-> click LTE BC Config DIV #6829

-> (3) read

-> then click the selected band you want to add

-> (4) write

goto (1) and repeat till (4)
about 3 times, because the settings were not saved, when done only once or twice.
The last steps were in my cases step (1) and (2).
When i read "LTE BC Config #6828" the 3rd time, it was saved.
Then reboot.
LTE Bands are after checking with QualcommTool saved, but i wasn't in a Band20 area till now, to check it practically.
Maybe some of you can test it.
Can you share QualcommTool.exe