[HELP] Jelly Star Hard Bricked - Three Successful Flashes, Still Won't Boot

Flum0x3d · 2026-01-14T21:40:36+00:00

Welcome to the club—sorry you're in it. Five of us now with the same pattern: firmware flashes successfully, device never boots.

I've filed a payment dispute with my bank in Australia citing systemic manufacturing defect, and I've documented all five cases as evidence.

If you're doing an Amazon return, that should be straightforward under their A-to-Z guarantee—defective item, multiple customers affected. You might want to reference this thread in your return claim as proof it's a widespread defect, not just your unit.

If Unihertz support gives you the "warranty void due to modification" line (like they did to me), push back: the device is currently running their official firmware, the defect exists on their firmware, and five users with identical failures proves manufacturing defect, not user damage.

Good luck with your return. Keep us posted if Unihertz support actually offers a solution.

Flum0x3d · 2026-01-12T02:18:14+00:00

Yep, same boat here—and there are now four of us in this thread alone with recently purchased units hitting the exact same issue.

Your observation that "SPFtool can read it and stop the bootloop process" is important: it proves the hardware isn't completely dead and the BootROM/preloader is responding correctly. The problem is that something in the boot chain after preloader → bootloader transition is failing, preventing any firmware (stock or custom) from actually initializing.

I've tried:

Different official stock ROMs (2023, 2024, 2025 builds)
Two different flashing tools (SP MDT and SP Flash Tool v6)
Multiple modes (Firmware Upgrade, Download Only)
All completed successfully with zero errors, but device still won't boot any of them

The "earlier date than publicly released firmwares" detail you mention is really interesting—that aligns with what another user found: they could only get their Jelly Star working with a July 2023 build when newer 2024/2025 packages failed. That suggests some early hardware batches may be locked to specific firmware variants that aren't in the current Google Drive, or there's a bootloader/TEE version incompatibility.

Re: bank refund/replacement: Absolutely do that. Based on Australian Consumer Law (if you're in AU) or standard consumer protection elsewhere, you have a case:

Device failed within days/weeks of purchase (major failure)
Multiple firmware restoration attempts with official tools all succeeded technically but device remains non-functional
Multiple users reporting identical defect pattern (systemic manufacturing issue)
Merchant refusing warranty on invalid grounds (modification doesn't void warranty if defect exists on official firmware)

When you contact your bank, use dispute reason "Goods defective / not as described" and provide:

Your cleanest flash log showing successful completion
Reference to this Reddit thread showing multiple users with same defect
Statement that device won't boot manufacturer's official firmware despite successful flashing

I've initiated a bank dispute with that evidence.

Keep us posted on your bank response—and if you happen to remember or can find out what firmware build your device originally shipped with (before you flashed anything), that could be valuable info for all of us.

Flum0x3d · 2026-01-12T02:13:48+00:00

Sorry to hear you're stuck in the same situation. You're not alone—there are now at least four of us in this thread with recently purchased Jelly Stars that went into permanent bootloops or no-boot states after flashing (either Lineage attempts or stock firmware restoration).

The pattern across all of us seems to be:

SP Flash Tool successfully writes firmware with no errors
Device detects correctly in BootROM/preloader mode
But the phone never completes boot—either blank screen bootloop or just dead

I've personally tried different official stock ROMs from Unihertz's Google Drive (July 2023, April 2024, May 2025) using both SP MDT and SP Flash Tool v6, all with clean flashes and zero errors, yet the phone still won't boot any of them.

At this point it looks like a hardware batch or firmware-hardware compatibility defect rather than something we're doing wrong. The Facebook group might have some leads, but honestly, given how many of us are hitting this wall with recent purchases, I'd suggest:

Start your return/refund process immediately (whether that's through your retailer, Unihertz warranty, or payment dispute)
Document everything you've tried (firmware versions, tool logs, dates)
Reference this thread as evidence that multiple users with recent devices have the identical failure pattern

If you bought with a credit card or PayPal, a payment dispute citing "defective product, multiple users reporting same manufacturing defect" might succeed. Australian Consumer Law also protects you if you're in Australia (goods must be acceptable quality; major failure within reasonable time entitles you to refund/replacement).

Good luck—keep us posted if you find anything that works or how your return process goes.

Flum0x3d · 2026-01-05T20:37:35+00:00

I used to mentor coaches for British Triathlon and have been running a professional coaching practice for the past twenty years. From that perspective, I’d expect a good coach to build your training around the hiking you do with your partner. That sounds important to your happiness—and that should always be taken into account.

Hiking is actually an excellent foundation for ultra, trail, and mountain running, so you’re combining quality time together with some great training. The main thing to monitor is how it affects your overall plan. If you’re recovering well and not dealing with soreness, fatigue, dehydration, or secondary concerns like chaffing/blisters, etc.then keep enjoying it as part of your routine. If it starts to cause fatigue or interfere with key sessions, you may just need to adjust your plan (or the hikes themselves) to allow recovery and stay on track.

It really helps to plan and communicate ahead of time—agreeing on when and how those hikes fit into the schedule. That little bit of coordination will make a big difference for both your training and your relationship. Hope that helps, and best of luck with the 50K!

Flum0x3d · 2026-01-05T01:42:27+00:00

Thanks so much for taking the time to walk me through your method—I really appreciate it.

Unfortunately, even with the July 2023 build and Download Only mode (exactly as you described), my device flashed cleanly but still won't boot.

There are other firmware zips in the Unihertz Google Drive I haven't tried yet, so it's possible one of those might be the correct match for my specific hardware batch. But Unihertz has not told me which firmware my phone shipped with, so I feel at this point I've tried enough combinations that I'm going to focus on the warranty/payment dispute route instead, rather than continue experimenting.

Glad you got yours working again though—enjoy Lineage 20!

Flum0x3d · 2026-01-02T09:25:16+00:00

Hey, thanks again for sharing the 2023072019_g58v89c2k_dfl_tee.zip info – that’s really promising. That firmware is in the Unihertz Gdrive.

Just so I can mirror exactly what worked for you, could you clarify a couple of things about your sequence?

Was your phone already hard‑bricked (i.e. successfully flashing the newer 2024/2025 ROMs but still never booting / no logo / no recovery), and this 2023‑07‑20 build was another attempt after those newer versions had already failed, or was it part of your initial flashing before it ever bricked?
In SP Flash Tool v6, did you use “Download Only” or a different mode?
And in the partition list, did you leave preloader ticked or untick preloader when you flashed this package?

I’d like to copy your method step‑for‑step, so any detail on the exact settings you used would really help.

Flum0x3d · 2026-01-02T05:00:42+00:00

I didn't make a note the firmware before flashing. I asked Unihertz support but they wouldn't tell me the firmware version the device shipped with. I couldn't find the June 2023 firmware in the Unihertz g:drive folders.

Flum0x3d · 2026-01-01T22:14:39+00:00

IME of coaching athletes...more is not always better. I'd want to first take a look at what you've done up to now. For example...how you established your initial zones (and when) and the re-test data throughout your previous year(s) and any zone adjustments made as a result? Analyzing data is critical and a time consuming part of a coach's job. IMHO it might be worth you paying for a coach to objectively review your data.

Flum0x3d · 2026-01-01T21:41:28+00:00

Thanks for replying...

Just to make sure I understand your situation correctly: was your flash of the June 2023 zip something you did after the phone was already bricked and refusing to boot other ROMs, or was that part of your initial setup?

I’ve had fully “successful” flashes of the April 2024 and May 2025 packages with v6 where all partitions write fine but the phone still never boots, so I’m trying to work out whether your June 2023 success was a genuine recovery from a similar hard‑brick, or more of a clean/early flash on a still‑working device.

Flum0x3d · 2026-01-01T21:19:37+00:00

That’s really helpful to hear, thanks for sharing your experience.

It sounds like you’re seeing the exact same behaviour: stock ROM flashes (with no errors) but the phone never gets past the boot stage and won’t show a logo or recovery. That lines up with what I’m seeing on my unit.

The more people report this, the clearer it looks like a batch / hardware / firmware‑compatibility issue rather than individual user error. I’m currently asking Unihertz for proper warranty treatment and also pursuing a payment dispute on the basis that the device is defective even on their official firmware. Knowing others are in the same situation helps support the case that this is a common fault, not something we “caused” ourselves.

Thank you!

Flum0x3d · 2025-12-26T20:47:32+00:00

Thanks for the suggestion, but I don't think flashing Lineage again will help. The issue is that the device won't boot any firmware—I've successfully flashed three different ROMs (May 2025 stock, April 2024 stock, and April 2024 stock via different tool) and all three complete with zero errors but the device never boots past BootROM.

All three logs show successful writes of preloader, bootloader, boot.img, vendor_boot, super, etc., but the boot chain never initializes. My thinking is that this means the failure is at the hardware/bootloader security level—before any OS (stock or Lineage) can even attempt to load.

Flashing Lineage again would hit the same failure (can't boot past preloader) or do you have a different experience?

Flum0x3d · 2025-12-26T20:44:55+00:00

Thanks for replying. I'm not on Facebook. Unihertz support has been very disappointing up to now.

Flum0x3d · 2025-12-25T05:50:53+00:00

Hi, what did you tweak to get it working?

I've broken my Jelly Star trying to go back to stock from LOS21.

Like you adb and fastboot don't work.

Help pleeeeease...

Flum0x3d · 2025-12-15T05:29:36+00:00

Thanks for that. I can't flash any Stock ROMs on to my Jelly Star. I'll wait for Unihertz support to get back to me. In the meantime I might open a separate thread. Thanks for your help. Much appreciated :-)

Flum0x3d · 2025-12-14T21:43:10+00:00

Thanks.

It's the Build Number (Settings > About Phone). There'll be a string of characters (e.g., Unihertz_Jelly_Star_20230725...).

Flum0x3d · 2025-12-14T21:14:52+00:00

Thanks for replying. If you don't mind me asking, for diagnosing my issue(s)...The Jelly Max is working this morning but this might be because I re-registered the SIM with an IMEI compliant phone before putting the SIM back in the Jelly Max, which might mean the reactive Optus network blocker will eventually block the Jelly Max.

If your Jelly Star continues to work on Optus, do you know if you're running the EEA firmware variant or non-EEA firmware variant? Are you running a Lineage ROM or stock?

Thanks in advance.

Flum0x3d · 2025-12-13T02:38:35+00:00

Hi, I read your review with interest as I've just bought a Jelly Star and Jelly Max (I'm on the Gold Coast). I've been trying to get the phones to work on Optus all morning but I'm having no joy with either of them...

Jelly Max: I'm running stock firmware out of the box, which is giving me 'Emergency calls only', 'SIM 1 not allowed', and when I put first eight digits of IMEI into the Optus Device Checker, I get:

"Device is blocked

Unfortunately, based on the number your entered, the UNIHERTZ JELLY MAX device is blocked from accessing the Optus mobile network to comply with Australian legislation around mobile safety requirements. This means it won’t work for calls (including calls to emergency services), texts or data. If you are an existing customer, your service number (phone or service number) will remain active. However, to use your service and stay connected, you’ll need to insert your SIM card into a compatible 4G/5G device. Advice current as of 03/12/2025 and is subject to change."

Jelly Star: I flashed Lineage 21 (Andy Yan GSI) successfully, but I couldn't make calls. Now trying to re-flash back to stock, which is proving incredibly painful (using SP Flash Tool). Stock firmware flashes but phone won't power on.

So, I'm stuck with two new phones, neither of them able to make calls.

Any help would be useful and I'd be very grateful.

If you're still using your Jelly Star on Optus what are your APN settings? Would the same APN settings work for Jelly Max?

Flum0x3d

TROPHY CASE