Hello. I'm reaching out to the community, and desperately seeking help. I bought a refurbished A53 on Amazon in 2023, model SM-A536U1/DS. It was functioning perfectly fine right up until the One UI 8 update. I let the update happen overnight, and I woke up the next morning to "No Service ๐ซ" (not "emergency calls only," not "no SIM." No service whatsoever.
I've run the entire gambit on this phone. Boot in safe mode, network reset, full reset. I even went so far as to use Odin to flash the firmware again, the one matching my phone's current state is A536U1UESIGYK2. It *still* isn't working. Using the Samsung Members' diagnostic tool, it checks for my SIM and says there's no SIM inserted. Not a single thing about my phone changed from the night to the morning, I didn't do anything to it physically that would suggest such damage. My SIM card and my service with my carrier are all intact and can function on an older device (an A51 I had from a few years prior to 2023.)
The A51 is working, but a lot of the features I've come to rely on aren't available because of how old the phone is. My Samsung Health data won't sync (tried unencrypting the data, repeated installations, no dice), I can't get my medication data (Samsung Health version is too old), can't use NFC or tap-to-pay, you name it.
I am beyond frustratedbecause I only got the phone two years ago, and it has been perfectly fine up to this point. I can't afford to buy a new phone, I can barely even afford to go to a shop and get it fixed, and even then, I have no idea what they'd do when nothing physically changed with my phone, and I've already performed a factory reset of the device. I tried contacting Samsung previously and they just told me to try and go to a service center or send my phone in. Even booking an appointment is met with hurdles because apparently the A53 isn't serviceable in my area, and I've wondered if it's a manufacturing thing or because of how I bought it (and I'm based in the US.)
I wish i had better news, but i rather give you an answer instead of leaving you without one. So this lines up with a known issue for some US unlocked A53 (SM-A536U1/DS) devices, where the One UI 8 update can break the modem/baseband and cause no SIM detected errors. Even though the phone seems fine otherwise, the update can corrupt or make the CP (modem) firmware incompatible with your device. Thatโs why reflashing just the system/AP didnโt fix it. The fix usually requires flashing the full firmware including the correct CP and CSC for your US unlocked model, or rolling back to the previous One UI version. Without this, the phone will remain unable to detect a SIM, and Samsung or authorized shops often only offer mail-in repair or a replacement. It sucks man, it really does, but the best bet is getting a mail in replacement. Im just giving it straight, there is nothing you can do. Its unfortunate, but there is a way for you to do it but its going to be highly stressful, infuriating, and very risky because it most likely can block it permanently... you'll need a pc too if you are willing to do it yourself but I cant stress enough about how risky it is and how stressful.
I respect the honesty, and certainly no ill-will towards you. As I did state before, I did use Odin to flash the firmware again, with all files (AP, BL, CP, CSC.) I did it to match my current version (most online comments indicated the binary must match or be "higher" than the current.) My bigger issue is that the binary I have is at its maximum, I cannot find any other firmware that exceeds it, and based on everything I'd read, I can't just "go backwards" with it.
So, yeah, crappy situation. Might have no choice but to send it in and hope Samsung can fix it.
If thatโs the case, and youโve already reflashed the exact matching firmware with Odin using BL, AP, CP, and CSC and youโre still stuck on No Service / no SIM detected, then the problem is almost certainly not something you can fix with normal user tools anymore. Once One UI 8 updated the phone, it also updated the bootloader/binary to its highest level, which blocks downgrading to older firmware, even if people online suggest โrolling back.โ Odin cannot rewrite parts kf the modem that may have been corrupted by the update, so reflashing the same or newer firmware wonโt help. At that point, the only real fixes left are a Samsung service center reflash using internal tools (not available to users) or device replacement. Unfortunately, this has happened to multiple A53 units after One UI 8, especially refurbished or region-mismatched models, and Samsung hasnโt released a public patch yet. In short, you didnโt do anything wrong, youโre not missing a secret firmware, and thereโs no safe way to go backward once the binary is maxed out. If possible, may I ask what carrier you use for the Sim card?
My carrier is Boost. I haven't really had any issues with it. Thank you for mentioning the refurbished device portion, as that's exactly what I have, but haven't seen as documented online. The region mismatch may also be of concern, as mine seems to be based for the US, but I can't help but wonder if maybe there's an issue there too.
I appreciate your help. My field of study is within tech and naturally, I love being able to get hands on, but, alas, I'm not omnipotent or all-knowing lol, and I'm still an end-user for a lot of things.
Hey, I know we just met here on Samsung Members, but I really wanted to help you out since your A53 basically stopped working after the update. I was thinking of getting you a phone as a small Christmas gesture so you can keep using all the features you need, like Samsung Health and NFC. Of course, only if youโre comfortable with that. I just thought it could make the holidays a bit easier for you. I donโt want to overstep, so no pressure at all. I know what its like to struggle and especially when it comes to tech, it can make life a little harder. I really wouldn't mind, I like to do random acts of kindness here and there. You can absolutely say no considering you dont know me, but I just thought I should offer.
I don't know what to say. I've been struggling for a long time being unemployed and trying to manage my health care. Your generosity is greatly appreciated, and I would love to accept, but with sad acknowledgement that I really cannot offer anything in return. If a random act of kindness, even if one-sided, is within your will, you are one kind individual of good spirit.
No worries, Im not made of money either, but maybe it will help get the upcoming year off to a good start. Im not sure where we can work out the details, I just know we would need to talk privately. Im not expecting anything in return its really not an issue at all.
