How To Guide G998U and G998U1 Firmware Links and Flashing Discussion Here

[mapl.ph]

No, that's not an AT&T version. All bands should be enabled in all firmwares, but whatever your Service Provider SW is set to is probably what determines priority

I live in the Philippines, I feel that flashing my unit to U1 locked me to US bands. I'm currently not receiving 5G signals on the phone. What I have is the 12/128 Snapdragon variant and my network here supports n78 (3500) 5G bands. Few questions below for clarification.

1. Will sm-g998u1 firmware lock me to US bands? As mentioned I'm not receiving 5G signals here in the Philippines.

2. Will flashing sm-g998w fix my issue with 5g signal?

Any help is appreciated. Thanks

 

[iBowToAndroid]

I live in the Philippines, I feel that flashing my unit to U1 locked me to US bands. I'm currently not receiving 5G signals on the phone. What I have is the 12/128 Snapdragon variant and my network here supports n78 (3500) 5G bands. Few questions below for clarification.

1. Will sm-g998u1 firmware lock me to US bands? As mentioned I'm not receiving 5G signals here in the Philippines.

2. Will flashing sm-g998w fix my issue with 5g signal?

Any help is appreciated. Thanks

You need to research and see which bands are supported by U1 and W models. It's possible that they don't support your bands at all, since you're on the other side of the world. If you want guaranteed band support, you always buy a model from your own country, not a different country

 

[Ptuk]

You need to research and see which bands are supported by U1 and W models. It's possible that they don't support your bands at all, since you're on the other side of the world. If you want guaranteed band support, you always buy a model from your own country, not a different country

That's precisely what he is doing by posting. As of last year n78 wasn't on u1 and w but it might yet be as I think this band is coming in to use in the US. Whether it gets facilitate by a carrier or by Samsung i don't know. There used to be a way of doing it via dialler codes.

 

[death365]

Why xaa code is taking so long for 4.1 ?

I might end up flashing via odin soon

 

[death365]

Finally available for G998U1 xxa

 

[blake .l]

I flashed the U1 firmware to my Sim locked and boot loader locked AT&T S21 Ultra 5G. Does it affect the 5G? as of now I don't have a 5G plan so it show LTE+ When I do get my 5G plan the phone should still work correctly and pick up the 5G signal correct? I thought under service provider it was supposed to change from ATT to XXA? mine says ATT/ATT,ATT/ATT

 

[iBowToAndroid]

When I do get my 5G plan the phone should still work correctly and pick up the 5G signal correct?

Yep

 

[death365]

April security patch

 

[kmdigital]

I flashed the U1 firmware to my Sim locked and boot loader locked AT&T S21 Ultra 5G. Does it affect the 5G? as of now I don't have a 5G plan so it show LTE+ When I do get my 5G plan the phone should still work correctly and pick up the 5G signal correct? I thought under service provider it was supposed to change from ATT to XXA? mine says ATT/ATT,ATT/ATT

Yes, since it was an ATT device originally it'll work great. However, if you switch carriers there's a good chance that it won't work properly. I have an unlocked TMo S21U that I flashed to U1, and it doesn't work properly with VZW 5G, though 4G LTE works great. This seems to be because the CSC is stuck on ATT/ATT/TMB/TMB. What's interesting is that prior to flashing to U1, it was ATT/XAE/TMB/TMB (because I originally used it with an ATT MVNO. However, now that I've switched to a VZW MVNO, it stays stuck on only ATT & TMB, and it will NOT switch to VZW. I think I've found the answer at the link below, but I haven't tried implementing this yet. Short version, is that flashing to U1 seems to break the carrier switching, and extra steps need to be taken to get what's needed. https://www.reddit.com/r/GalaxyS21/comments/roqwkc

 

[blake .l]

Ok this is the first time I noticed this but I went from the G998U to the G998U1 version of the firmware and my check for update button is gone. Is this normal? I dont guess its a big deal as long as I can get new firmware downloads over the net or here when they are available

 

[kmdigital]

No, mine still there, so it should be on your's too.

 

[Limon_Lime]

Hello, I'm having an issue getting Visible service working on my Galaxy S21 Ultra SM-G998U1.

I purchased the phone on Swappa so I'm not sure exactly what carrier or model its from. But it should be factory unlocked and I can't call, text, or get data.

I tried installing a Verizon sim but still nothing. T-Mobile sim works perfectly though. And I've tried all the troubleshooting steps like network reset, adding APNs, even factory reset.

When I boot the phone or cycle airplane mode, occasionally 5G will turn on for a few seconds and immediately disconnect again.

The APNs all install automatically when I put the SIM in but i just don't get any service, even though it's showing full bars.

 

[kmdigital]

Are you 100% sure that it's a factory U1 phone? It sounds like it was a U phone, specifically for T-mobile, and if it says U1, someone flashed it to U1 even though it originally was a U phone. Go to About Phone/Software Information, and then about the 9th line down to Service Provider Software Version and let us know what it says. It will very likely have TMB as the last of 4 listed codes, and more than likely, it'll be TMB on at least 3 out of the 4 codes.

 

[Limon_Lime]

Are you 100% sure that it's a factory U1 phone? It sounds like it was a U phone, specifically for T-mobile, and if it says U1, someone flashed it to U1 even though it originally was a U phone. Go to About Phone/Software Information, and then about the 9th line down to Service Provider Software Version and let us know what it says. It will very likely have TMB as the last of 4 listed codes, and more than likely, it'll be TMB on at least 3 out of the 4 codes.

It says ATT/ATT/ATT/VZW

Does that mean it was originally an ATT or Verizon phone?

 

[kmdigital]

No, it was originally a Verizon phone, interestingly enough. However, it was then used on ATT, and for whatever reason, it's not properly picking up the VZW CSC and switching back to it again. If it were at factory U1 phone, the CSC would be XAA on at least 2 of them, and it would automatically switch to VZW when the SIM is installed. In another thread, after a lot of research, it seems that the S21 phones, even when flashed to U1, aren't true U1 phones and will always keep the original vendor as the last code in the CSC list. I had a similar issue with Visible on an original TMB phone, and this is how I resolved it,

S21 Ultra, originally T-Mobile, now Visible (Verizon), but doesn't have correct bands for 5g

I bought an unlocked S21 Ultra last fall that was originally sold by T-Mobile, and I initially used it with H2o (AT&T) and it always worked fine, though it never got 5g service, though I'm not sure that 5g has been implemented yet by AT&T in the...

forum.xda-developers.com

It's not difficult (though it does take about 15 - 30 minutes depending on how long it takes to download everything that you need), particularly on a brand new phone where you don't have things set up yet. If you have the phone configured and don't want to redo everything, then you'll need to use the Home CSC file as described, not the other one. If nothing is configured, then I'd probably use the other one. Basically, you need to reflash to U VZW and call that good if you don't mind the Verizon bloatware, or flash it again to either U1 VZW or U1 XAA to get rid of the bloatware. I'm not sure if U1 VZW has bloatware or not, but it may. I do know that XAA doesn't, and I really like the Smart caller ID function that I got after flashing to U1. Essentially, that seems to use any publicly available Google phone number info and automatically provide the caller ID name for any dialed or received calls. This may or may not be on the VZW firmware, as I didn't try it.

 

[Limon_Lime]

No, it was originally a Verizon phone, interestingly enough. However, it was then used on ATT, and for whatever reason, it's not properly picking up the VZW CSC and switching back to it again. If it were at factory U1 phone, the CSC would be XAA on at least 2 of them, and it would automatically switch to VZW when the SIM is installed. In another thread, after a lot of research, it seems that the S21 phones, even when flashed to U1, aren't true U1 phones and will always keep the original vendor as the last code in the CSC list. I had a similar issue with Visible on an original TMB phone, and this is how I resolved it,

S21 Ultra, originally T-Mobile, now Visible (Verizon), but doesn't have correct bands for 5g

I bought an unlocked S21 Ultra last fall that was originally sold by T-Mobile, and I initially used it with H2o (AT&T) and it always worked fine, though it never got 5g service, though I'm not sure that 5g has been implemented yet by AT&T in the...

forum.xda-developers.com

It's not difficult (though it does take about 15 - 30 minutes depending on how long it takes to download everything that you need), particularly on a brand new phone where you don't have things set up yet. If you have the phone configured and don't want to redo everything, then you'll need to use the Home CSC file as described, not the other one. If nothing is configured, then I'd probably use the other one. Basically, you need to reflash to U VZW and call that good if you don't mind the Verizon bloatware, or flash it again to either U1 VZW or U1 XAA to get rid of the bloatware. I'm not sure if U1 VZW has bloatware or not, but it may. I do know that XAA doesn't, and I really like the Smart caller ID function that I got after flashing to U1. Essentially, that seems to use any publicly available Google phone number info and automatically provide the caller ID name for any dialed or received calls. This may or may not be on the VZW firmware, as I didn't try it.

Ok so I tried downloading the latest VZW firmware from samfw.com.. but it gave me an AT&T logo on boot.

 

[kmdigital]

You need to install the Verizon SIM to make it switch, so you should have flashed it without any SIM in it, or with the Verizon SIM. Have you tried that? When you insert the Verizon SIM it should tell you to reboot it, at which time it'll now come up with the Verizon logo. You can leave it at that or reflash again to XAA U1 to get rid of the logo on boot.

 

[Limon_Lime]

You need to install the Verizon SIM to make it switch, so you should have flashed it without any SIM in it, or with the Verizon SIM. Have you tried that? When you insert the Verizon SIM it should tell you to reboot it, at which time it'll now come up with the Verizon logo. You can leave it at that or reflash again to XAA U1 to get rid of the logo on boot.

It doesn't ask me to reboot, just pulls up the SIM card info and allows me to press "Done".

I flashed it with the Visible sim inside but it still had an ATT logo on boot.

 

[kmdigital]

Hmm, it won't work unless it reboots to Verizon when the SIM is installed. I'd remove the Visible sim, reflash again making sure that you're using the U VZW firmware, reboot and then insert the SIM. It worked for me....

 

[Limon_Lime]

Hmm, it won't work unless it reboots to Verizon when the SIM is installed. I'd remove the Visible sim, reflash again making sure that you're using the U VZW firmware, reboot and then insert the SIM. It worked for me....

I flashed Samfw.com_SM-G998U_VZW_G998USQS5CVCB_fac.zip. Is that supposed to be the right one?