Invalid sim card issues on my S8 question

[Dconn1975]

So I have a sprint S8. I flashed it and removed all of the Sprint bloat ware and any traces of sprint branding. Now my S8 appears to look like it came directly from Samsung unlocked. My question is this. Sprint has told me it's unlocked but when I put my cricket sim in it, it still says invalid sim card. I also loose my APN settings option too. Does anyone know how I can get this fixed or get around it? I even paid $55 to have it fully unlocked but even still it says invalid sim. Does anyone have any ideas of what I can do or has anyone had this same issue with their S8? Any help would be greatly appreciated. It's very frustrating. It works just fine with my sprint sim though. Thanks for any help or advice.

 

[anon(238680)]

Is this the same S8 you're trying to sell as nearly new in the box? Just curious as I read your ad here on the forum.

 

[Dconn1975]

Is this the same S8 you're trying to sell as nearly new in the box? Just curious as I read your ad here on the forum.

Yes it's my S8 I'm selling. I have it posted of course as a sprint device as even though it's unlocked without doubt my cricket sim says invalid so I know for sure sprint works just fine. I've got it listed for a quick sell though so whoever buys it is going to get the deal of the century on it. It's already marked down low enough to make it worth just buying it as a wifi device actually. I'm wide open to all offers right now. I decided I'm going back to an Honor 8 as I'm a huge fan of EMUI software. My other choice is the Moto Z Play. I love the S8 but I used the honor 8 for so long that I miss it.

 

[mary beth hale]

Read some other posts of yours re: flashing a different firmware. Just curious... Did you actually input a sim unlock code? I don't think flashing to get rid of carrier bloat actually sim unlocks the phone.

 

[Rukbat]

Cricket is a GSM carrier (it uses AT&T's network - in fact, it's owned by AT&T). A Sprint phone is a CDMA phone. One won't work on the other. (CDMA phones aren't locked - at all. But the carrier may not accept a phone that's not theirs - that's the "locking mechanism" on CDMA phones.)

Either whoever you paid to "unlock" it caused a problem, or you removed some file it needs to accept the SIM.

My suggestion is that you reflash the stock ROM (back up everything first - you'll lose it all). Then, if you still think that you know what you're doing, root the ROM and remove the bloatware. (But if you're selling it - as a CDMA S8 - don't play with it. Let the buyer root, "remove bloatware" and anything else they want to do. And flashing a ROM doesn't change the state of the SIM-lock. If it's unlocked, it will stay unlocked.)

See [Samsung] How to flash Stock ROM via ODIN for flashing instructions. It may look scary, but it's actually very boring.

 

[anon(7901790)]

Both Sprint and AT&T are SIM locked (unlike T-Mobile and Verizon).

https://www.sprint.com/en/legal/legal-regulatory-and-consumer-resources?ECID=vanity:legal

Your Sprint S8 is "unlock capable." Not unlocked.

Unlocking Requirements
Sprint will unlock a device from Sprint's network under the following circumstances:

The device is SIM Unlock capable
The device must be or have been active on the Sprint network for a minimum of 50 days
Any associated Service Agreement (or any Minimum Service Term, where applicable), Installment Billing Agreement, or Lease Agreement has been fulfilled including, but not limited to, payment in full of any applicable: 1) early termination fees, 2) accelerated installment or lease payments, and/or 3) end-of-lease purchase options. Because leased devices are not owned by the user, the end of lease purchase option must be exercised and paid in full before the SIM unlock is completed.
The associated account is in good standing
The device has not been reported as lost or stolen, associated with fraudulent activity, or otherwise flagged as ineligible to be unlocked
For SIM unlock-capable devices launched after February 2015, Sprint will automatically unlock the device when it becomes eligible.

For inactive devices, customers must contact Sprint Customer Care to request that their SIM unlock-capable device be unlocked and may have to take steps to perform an over-the-air update to ensure the unlock programming has been relayed to the device. Additional validation may be required to ensure eligibility.

Sprint makes no guaranty that an unlocked device will work on another carrier's network. Whether another carrier will accept and activate a device is subject to that carrier's policies and capabilities. Additionally, Sprint devices which the owner has attempted to reprogram or activate on another carrier's network or otherwise altered from its initial programming or settings may not be able to be reactivated on the Sprint network.​

 

[anon(7901790)]

Cricket is a GSM carrier (it uses AT&T's network - in fact, it's owned by AT&T). A Sprint phone is a CDMA phone. One won't work on the other. (CDMA phones aren't locked - at all. But the carrier may not accept a phone that's not theirs - that's the "locking mechanism" on CDMA phones.)

Not quite true. It depends on the carrier that phone is branded to. In this case both Sprint and AT&T are SIM locked. Therefore, Sprint has to unlock the phone (reference my previous post) for it to work on other networks. Verizon and T-Mobile are not SIM locked and can be used on other non-CDMA networks. I can take my Verizon S8+ and use it an AT&T or T-Mobile SIM and it'll work. All I need to do is pop in an activated SIM.

In fact, as I am writing this, I am using my Verizon S8+ in Okinawa, using Travel Pass. Both Japanese carriers are GSM/LTE and my phone connected no problem. If you are wondering about cost. It's costing me $10/day and I get to keep my unlimited texting, voice and data.

Furthermore, there are some phones like the HTC U11 that work on Verizon's network. The U11 does NOT have CDMA enabled.

 

[mary beth hale]

As far as the Galaxy S8/s8+ go, I thought only the US unlocked had both the GSM and CDMA radios.

 

[anon(7901790)]

As far as the Galaxy S8/s8+ go, I thought only the US unlocked had both the GSM and CDMA radios.

To my knowledge, all unlocked S8/S8+ have CDMA and GSM/LTE radios enabled. There are other non-US CDMA carriers. About 100 worldwide I believe.

 

[Dconn1975]

Well I sold it being on Sprint and my work is giving me a new 128g iPhone 7 plus I've got a cricket line that I'll probably use an honor 8, Moto Z Play or Axon 7 on. I was not a fan of sprint at all though. I've used cricket so long now that I had forgotten how at times difficult it can be tied to a carrier which outside of my free work phone I won't be anymore. I'll stick with buying unlocked devices and keep using cricket.

 

[mary beth hale]

To my knowledge, all unlocked S8/S8+ have CDMA and GSM/LTE radios enabled. There are other non-US CDMA carriers. About 100 worldwide I believe.

You're right. Was just referring to US models.

 

[mary beth hale]

Well I sold it being on Sprint and my work is giving me a new 128g iPhone 7 plus I've got a cricket line that I'll probably use an honor 8, Moto Z Play or Axon 7 on. I was not a fan of sprint at all though. I've used cricket so long now that I had forgotten how at times difficult it can be tied to a carrier which outside of my free work phone I won't be anymore. I'll stick with buying unlocked devices and keep using cricket.

Sounds like you're happy with the decision to sell the Samsung. That's great. I have purchased unlocked phones for past 6 years and have never missed being tied to a carrier.