How to Solve Thecus D0204 and JMS539 Auto-Disconnect Issue

Thecus D0204 is a Direct-attached storage (DAS) supports two 2.5″ hard drive in RAID 0, 1, JBOD, and two individuals. According to “USB 3.0加持,Thecus D0204小DAS跑得快” on T客邦, it use JMB390 for RAID and JMS539 for SATAII to USB 3.0 bridge.

My problems is it will automatically disconnect and reconnect immediately with OSX. But I was wrong, there are already many posts about the same issue. It’s due to the bugs in JMS539 according to “[心得] Mukii3.5吋硬碟外接盒起死回生紀錄” on 批踢踢實業坊.

Upgrade Firmware

I have check official product page for D0204 but there is nothing to help. On the other hand, “2011年06月10日 JMS539 USB3.0ブリッジを使用した製品の注意事項” on KingTech provides detail explain and solution. For D0204, you need to download patch and follow the steps:

  1. Plugin D0204 to your Windows computer and turn on.
  2. Run FwUpdateTool_v1_16_00_T2.exe
  3. Choose any hard drive in D0204 in USB DISK and the Chips should be JMS551/539 Series.
  4. Make sure it loads JMS539_PM_255. in Firmware File
  5. Click on [Run]
  6. If success, you will see Programming Success!! in Status. It also pop-up a message dialog to restart D0204.

Okay, done. I didn’t see any disconnection after firmware upgrade now.

For Firmware Older than

You need to search for other firmware before upgrading to For example, “SuperSpeed USB 3.0 Device Firmware Update” on Vantec’s Knowledge Base contains instructions and download for  JMS539FwUpdateTool_v03(NST-280S3, NST-310S3, NST-D300S3).zip.

Good luck!


  1. Apple: OS X
  2. JMS539
  3. JMicron: JMB390
  4. KingTech: 2011年06月10日 JMS539 USB3.0ブリッジを使用した製品の注意事項
  5. KingTech: JMS539 USB3.0ブリッジファームウェア更新_USB3.0HBA設定ファイル 
  6. Thecus: D0204
  7. T客邦:USB 3.0加持,Thecus D0204小DAS跑得快
  8. Vantec: Knowledge Base
  9. Wiki: Direct-attached storage
  10. Wiki: RAID
  11. 批踢踢實業坊:[心得] Mukii3.5吋硬碟外接盒起死回生紀錄
  12. 批踢踢實業坊:Re: [心得] usb 3.0 一些事情碎碎唸 orz…

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.