Inspiron 15 3530, BIOS 1.28.0, broken fan behavior

Question

Hi all, my Inspiron 15 3530 recently updated to BIOS 1.28.0 automatically through LVFS, the issue is it caused my fan to stop working completely when booted into an OS. More specifically, the controller seems to "freeze" once it gets out of POST, meaning if the computer is hot while booting it will "freeze" at 100% PWM duty cycle and if it's cold (like most boot events) it will get stuck at 0% PWM, 0 RPM.

I've isolated this to a BIOS issue since:

- I tried three Linux distributions and two Windows 11 installs, all five instances with the same behavior

- I tried reflashing the same 1.28 update (downloaded from LVFS) and it successfully flashed with no changes in behavior

- The BIOS can perfectly control the fan, as I tested it from the BIOS' Diagnostics screen and the fans responded properly (I've also fully cleaned the entire laptop so it's not a physical blockage either)

The BIOS can NOT be rolled back to the previous version (1.24.1), I have AdvancedMode enabled so I could turn BIOS rollbacks on. The 1.28 update apparently pushed the minimum version. I tried flashing 1.24.1 both from Dell's official support page (for my serial number) and LVFS's .bin. No luck.

I'm fairly sure this is an Embedded Controller issue, since trying to write directly to dell_smm's hwmon has no effect at all. What I mean is, trying to write to /sys/class/hwmon/hwmon4/pwm1. In some cases the system boots and pwm1 randomly changes between 0 and 128, and in some others it's just locked to 255.

Is this the correct place to report BIOS problems? Thank you.

Maddock

maddock · Accepted Answer

UPDATE: This was fixed in the 1.30.0 BIOS update (Dell response)!

LSUFAN51 · Answer

You could use Help Now feature at the right bottom of the page to start a live chat session. Hopefully this will help start a Technical Support case for you. Good luck.

DELL-ChrisM2 · Answer

Did you test the BIOS 1.29.0 released on 27 Feb 2026?

maddock · Answer

@DELL-ChrisM2​ Hi! Yes, I'm running it right now. The fan behaves the same sadly, even though 1.29 introduced a minor update to the EC, I think to 0.10.1 or something like that.

rnnto_ · Answer

@maddock​ wow, remarkable work from Dell! I had to block automatic driver updates from Windows to stay on 1.24.1 after support downgraded for me. How is it that they managed to make 4 funky BIOS updates in a row? 1.25.1, 1.27.0, 1.28.0 and 1.29.0 are all bad! I believe you're better off calling support and asking for a downgrade to 1.24.1, the last known working version. Dell really fell off.

Harsh Gupta · Answer

@rnnto_​ I have the same problem but i complaint to dell and they replace the motherboard . Luckily my laptop was in warrenty but i am disappointment from dell that my laptop have 2 motherboard replacement, 1 daughterboard replacement, 1 ram replacement even the laptop is not even done 1 year of buying.  My opinion is to wait if you don't have warrenty otherwise complaint dell for motherboard replacement if the laptop is under warrenty.

BetoBR · Answer

Hi everyone,

I want to share my experience with the fan control bug introduced in BIOS 1.28.0 on the Inspiron 15 3530, and a temporary workaround I found while waiting for a proper fix.

My fan was randomly stopping under heavy load, causing the CPU to reach 100°C before the system would throttle. The fan worked perfectly in the BIOS diagnostics (reaching 5,800 RPM), confirming this was not a hardware failure.

After extensive troubleshooting on Linux, I tried every software approach: reloading the dell_smm_hwmon driver with force=1, ignore_dmi=1 and restricted=0 parameters, attempting direct PWM control via /sys/class/hwmon, and installing thermald. None of these worked because the firmware retains full control over the fan.

Eventually I identified the root cause: BIOS 1.28.0 is sending a PWM=0% signal to the fan under certain load conditions, which causes it to stop completely. This is a firmware bug, not a hardware or OS issue.

Temporary workaround (use at your own risk):
With the laptop open, physically disconnect the blue PWM wire from the fan connector. Without the PWM signal, the fan runs at full speed constantly and cannot be stopped by the firmware. The CPU temperature on my unit dropped from 100°C under load to around 38°C at idle.

Notes:
- The tachometer reading will show erratic values or zero without the PWM reference — this is expected and harmless
- The fan will be noisy running at full speed
- This is fully reversible — just reconnect the blue wire once a fixed BIOS is released
- Please reference Dell article 000423130 when contacting support about this issue

I hope this helps others dealing with this frustrating bug. Please Dell, prioritize a BIOS 1.29.0 fix — this is causing real hardware stress for many users.

Best regards

Harsh Gupta211 · Answer

You will not believe what I got answer

From ATS ( advance resolution service) that this is FINE and said that to take it to service centre and they also said this problem fine literally. After some conversations with ats, they said that it will not rotate because while in bios, the laptop is not under stress and fan will not rotate, even they saw the high temperature

maddock · Answer

@rnnto_​ well I'm gonna play devil's advocate a bit here. Dell seems to share BIOS versions across pretty much all of their laptops, so I assume 1.25.1 updated something Inspiron 15 3530-specific that broke fan behavior and the following updates were just 'upstreams' to the mainline, shared (common) BIOS code. Still a bummer though! I thankfully managed to fix this somewhat unofficially and in a hacky way using an engineering BIOS.

maddock · Answer

@BetoBR​ hi there! this might be a bit extreme. When I still had this issue I would just bump/move the laptop a bit and then the controller would 'wake up' and tell fans to go the proper speed. I wouldn't really go down there touching cables (especially the fan ones since they're quite narrow and fragile) and risking permanently damaging or locking the fan at 100%. There's a hacky workaround I managed to use to downgrade back to 1.24.1 using an engineering BIOS, I can help you if you need it.

dhruv_s2424 · Answer

Yes @maddock happening same in my laptop too..

Above that Dell Support assist had delivered 1.27 after that i removed it and manually updated to 1.29 sadly it didn't fix the bug.

I think dell should hesitate as they didn't properly test the bios before releasing such updates. Also after playing email-email with support agent they said do a os reinstall and take to nearest service centre.

Who is going to pay after going to the service centre? Also a fix is taking so long almost 2 month since 1.27 came.

This is a very critical issue CPU and can get damaged due to heat.

@dell Please work on a solution ASAP. Users are waiting since 2 months

Inspiron

Inspiron 15 3530, BIOS 1.28.0, broken fan behavior

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