Your server's fan curve is likely set to "silent" or "balanced." During a firmware update, override the fan profile to 100%. The flash process takes 60-120 seconds of high CPU usage on the expander. Without 400+ LFM of airflow, you will overheat.
Run the SAS flasher with "aggressive" flags. Example for Broadcom/LSI:
sas2flash -o -e 6 (Full chip erase, including protected sectors)
sas2flash -o -f 2520uz2_correct_firmware.bin -b mptsas2.rom
SAS expanders are sensitive to voltage droop. If your drives are reading/writing during a flash, the 12V rail sags, and the expander undervolts during the write cycle. This corrupts the firmware 100% of the time. Always flash from a maintenance OS or bootable USB with zero disk I/O. dsl2520uz2 firmware hot
When you push new firmware (via sas2flash or the manufacturer’s utility), the chip erases the old NVRAM and writes the new binary. If the checksum fails or the image is for the wrong SKU (e.g., DSL2520UZ2 vs. DSL2520UZ1), the chip enters a "safe mode" boot loop.
| Step | Action |
|------|--------|
| 1 | Check firmware version: 192.168.1.1 → Maintenance → Firmware |
| 2 | Downgrade to last stable release (e.g., IN_1.04 or earlier) |
| 3 | Disable TR-069 & WPS (reduces CPU background tasks) |
| 4 | Improve ventilation – stand vertically or add a small USB fan |
| 5 | Reset to factory defaults after firmware change (crucial!) | Your server's fan curve is likely set to
Do not cross-flash. A Dell DSL2520UZ2 has different I2C addresses for SGPIO (LEDs) than a Supermicro version. Flashing the wrong vendor's firmware will not brick the chip but will cause the PHYs to "rail" (stay open), generating massive heat. Compare the MD5 checksum before flashing.
How do you know your DSL2520UZ2 is suffering from a firmware-related thermal issue? Look for these signs: SAS expanders are sensitive to voltage droop
WARNING: Do not attempt to "let it cool down" and reflash while the system is powered on. If the chip is in a thermal runaway state due to firmware corruption, you risk shorting the backplane.
If issues persist, revert to 2.1.0.2 using:
fwupgrade -rollback 2.1.0.2
(Stored in reserved partition)