Sim toggles on and off

[ross86]

Using Unihertz Jelly Pro. Since Android Update 8.1 I can't use my sim card in my jelly pro phone.  There is a toggle to select sim card which repeatedly turns on and off by itself and won't stay connected. Happens a few times a minute. I have tried factory reset, using the sim card in another older phone (works on other phone) and trying my partner's sim card in my phone (sim card works in her phone). 

Any suggestions? 

[Psygineer]

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@will13am wrote:

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Actually, the latest android phones use so called A/B partition to store one known working backup.  After an update, the system will only the new update if there are no faults detected.  For Oreo onward, absolutely don't roll back.  Anti rollback security will block the roll back and in some instances soft brick the phone.  The soft brick is model dependant.  Xiaomi is known to use soft brick.

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That is definitely a good feature to have added, I guess with devices coming with more and more internal storage they have finally decided they can waste a little space with safety measures rather than taking the whole que sera sera approach to updates/upgrades. My devices are all older now, looking to upgrade soon to something else (Oneplus 6 or Asus ROG Phone have caught my eye) so they all lack that feature, but I am glad to be stood corrected! I never liked having to backup my O/S (or find one) just to flip back if something went nutty.

[Psygineer]

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@will13am wrote:

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@ShawnC13 wrote:

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@ross86 wrote:

Using Unihertz Jelly Pro. Since Android Update 8.1 I can't use my sim card in my jelly pro phone.  There is a toggle to select sim card which repeatedly turns on and off by itself and won't stay connected. Happens a few times a minute. I have tried factory reset, using the sim card in another older phone (works on other phone) and trying my partner's sim card in my phone (sim card works in her phone). 

Any suggestions? 

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When you put your partner's sim in your phone does it still toggle on and off?  This sounds more like a hardware issue rather than anything to do with the SIM.  I am relatively new to Android can you roll back from 8.1 if you had no issues with your previous OS

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Android had implemented anti rollback in oreo for security reasons.  Performing a rollback makes known exploits available.  Flashing older firmware results in a soft brick.  As the old warning goes "DO NOT TRY THIS AT HOME!"

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That's interesting, I must have missed that. I know I have rolled back Oreo before without issue, however, I can see why they would implement something like that.

[will13am]

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@Psygineer wrote:

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@ross86 wrote:

I can't seem to figure out how to roll back, will keep trying! 

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You can't roll back an Android like you can a Windows machine. It doesn't waste space keeping backups of former versions. Factory wiping doesn't reset the O/S back to an earlier version either. The only way (that I am aware of, I am sure there are likely other ways) to downgrade is to flash the firmware yourself, losing all data on the phone in the process, with a compatible earlier version you find online yourself. Then, depending on the phone, entering recovery mode should let you flash the firmware back with the compatible one you downloaded. The other method involves sideloading with ADB. I won't go through the details in a post like this as I don't want to take any responsibility if you brick your device, however, there is enough in my message here to get you started down the right track (if this is what you want). Also anyone else out there, I welcome you informing me and OP of a better way to do this!

Actually, the latest android phones use so called A/B partition to store one known working backup.  After an update, the system will only the new update if there are no faults detected.  For Oreo onward, absolutely don't roll back.  Anti rollback security will block the roll back and in some instances soft brick the phone.  The soft brick is model dependant.  Xiaomi is known to use soft brick.

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[will13am]

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@ShawnC13 wrote:

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@ross86 wrote:

Using Unihertz Jelly Pro. Since Android Update 8.1 I can't use my sim card in my jelly pro phone.  There is a toggle to select sim card which repeatedly turns on and off by itself and won't stay connected. Happens a few times a minute. I have tried factory reset, using the sim card in another older phone (works on other phone) and trying my partner's sim card in my phone (sim card works in her phone). 

Any suggestions? 

---

When you put your partner's sim in your phone does it still toggle on and off?  This sounds more like a hardware issue rather than anything to do with the SIM.  I am relatively new to Android can you roll back from 8.1 if you had no issues with your previous OS

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Android had implemented anti rollback in oreo for security reasons.  Performing a rollback makes known exploits available.  Flashing older firmware results in a soft brick.  As the old warning goes "DO NOT TRY THIS AT HOME!"

[popping]

@Psygineer

You are right.  For Android, the phone needs to reboot into recovery to do any roll back.  It is easiest to flash the backup if @ross86 did a image full backup before updating to Android 8.1.  Otherwise, as you said - lots of work.

@ross86

Read the following thread and contact Unihertz for help.  Good luck.

https://www.unihertz.com/bbs/forum.php?mod=viewthread&tid=61608&extra=page%3D1

[Psygineer]

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@ross86 wrote:

I can't seem to figure out how to roll back, will keep trying! 

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You can't roll back an Android like you can a Windows machine. It doesn't waste space keeping backups of former versions. Factory wiping doesn't reset the O/S back to an earlier version either. The only way (that I am aware of, I am sure there are likely other ways) to downgrade is to flash the firmware yourself, losing all data on the phone in the process, with a compatible earlier version you find online yourself. Then, depending on the phone, entering recovery mode should let you flash the firmware back with the compatible one you downloaded. The other method involves sideloading with ADB. I won't go through the details in a post like this as I don't want to take any responsibility if you brick your device, however, there is enough in my message here to get you started down the right track (if this is what you want). Also anyone else out there, I welcome you informing me and OP of a better way to do this!

[ross86]

I can't seem to figure out how to roll back, will keep trying! 

[ShawnC13]

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@ross86 wrote:

@ShawnC13 When my partner's sim in my phone it still toggles on and off (in my phone). In my partner's phone she gets full cellular and no toggling. 

With two different sim cards from two other phones the Jelly still toggles on and off. both sim cards work in other phones. 

You're right, it does seem like a hardware issue. 

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Has to be a hardware issue.  Can you roll back the latest update?  See if that works.

[ross86]

@ShawnC13 When my partner's sim in my phone it still toggles on and off (in my phone). In my partner's phone she gets full cellular and no toggling. 

With two different sim cards from two other phones the Jelly still toggles on and off. both sim cards work in other phones. 

You're right, it does seem like a hardware issue. 

[will13am]

Looks like something is wrong with the phone.  Not exactly sure what.  I have never experienced anything like this.

[ShawnC13]

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@ross86 wrote:

Using Unihertz Jelly Pro. Since Android Update 8.1 I can't use my sim card in my jelly pro phone.  There is a toggle to select sim card which repeatedly turns on and off by itself and won't stay connected. Happens a few times a minute. I have tried factory reset, using the sim card in another older phone (works on other phone) and trying my partner's sim card in my phone (sim card works in her phone). 

Any suggestions? 

---

When you put your partner's sim in your phone does it still toggle on and off?  This sounds more like a hardware issue rather than anything to do with the SIM.  I am relatively new to Android can you roll back from 8.1 if you had no issues with your previous OS