Hooking Up an HDD to Pioneer Car Audio CD-UB100 USB Adapter

The following article is a review of Pioneer CD-UB100 and how to format a portable hard disk to work with Pioneer’s USB adapter.
Pioneer CD-UB100

What Pioneer engineers achieved in making a USB add-on to their P-series headunits is quite impressive! I am mocking them wise Japs, because the CD-UB100 is twenty century’s technology sold in the twenty first!

It’s faced with many limitations and inconveniences especially when used in conjunction with portable hard disk drives, and what bothers me is all the troubles and limitations every consumer’s gonna face is because it’s designed to work with flash memory thumb drives first hand, and then they decided why not legalize hard disk drives as well. They spend millions every year to promote their different lines of product, but don’t bother designing something practical.

What’s more annoying is that we’re aware of their talent, I mean, come on, it’s the same company that makes an optical amp with a variable crossover capable of a mind-blowingly deep cut slope of -72 dB/oct! Yes, I’m talking about the ODR-series RS-A9. I wish CD-UB100 was more of an ODR- or at least PRS-engineering than the junk it is.

Stupid Limitations (aka “Compatibility” in Owner’s Manual Published by Pioneer)

  • Maximum amount of memory: 250 GB
  • Maximum files: 15,000
  • Maximum folders: 500
  • File system: FAT12, FAT16, and FAT32
  • Partitioning: Not supported
Pioneer CD-UB100 Disassembled PCB View

Why Stupid?

Take any portable 2.5” HDD manufacturer, their mid-size storage solution is around 320 GB at the moment. Within a year from now, no below-250 GB 2.5” portable HDD (120 GB/160 GB/250 GB) is gonna be available as first hand. A multi-terabyte compatibility limitation wouldn’t sound just fine nowadays!

Then it’s time to divide our maximum 15000 files into 500 maximum folders, getting 30 as result. How many music albums do you recall with 30 tracks? Now divide our maximum 250 GB capacity into 15000 files, getting a 16.6 MB average file size, which is even more than any typical insane-quality 320 kbps MP3 track. For 250 GB, it should be supporting a minimum of around 83000 files and 8300 folders.

Then it’s limited to FAT32 (introduced in 1996, let’s not forget, it also supports the dead 80s FAT12 and FAT16) and let’s not forget about the limitations we’re faced with, such as inability of Windows to format a FAT32 partition larger than 32 GB.

If you’re thinking of dividing your 250 GB disk into 8 (yes, freaky eight) partitions so it becomes FAT32-formattable, then you’d be wrong, very wrong: Partitioning is not compatible, and by that, those geeks at Pioneer Corporations meant the disk should have one single primary partition! But don’t get disappointed, there is a tool to FAT32-format a 250 GB (even a 2 terabyte) single-partition disk. The reason behind Microsoft’s decision to support mounting (reading) a pre-formatted larger-than-32-GB FAT32 partition and not formatting it, is because Microsoft technicians saw read/write operations on a big FAT32 partition is way slower than on say an NTFS partition; so in their wisdom, they decided to drop the format feature, may the people drop the 90s technology in advance.

How To Partition and Format Your Portable HDD in a Pioneer-Satisfying Fashion

Before you start any operation keep in mind you’re gonna need administrative privileges to perform partitioning and formatting operations. So if you’re the admin and Windows still bothers you complaining about files being open, just run Sysinternals Process Explorer, hit Ctrl+F, type the drive letter plus colon (e.g. E:) to find out which process is guilty of having it open, and close it.

If your drive has anything other than a single primary partition, it needs repartitioning. First you need to delete any previously-defined partitions, and define one primary partition covering the whole space of the physical disk, utilizing Windows Disk Management. To start Disk Management, type diskmgmt.msc in “Run…” and press Enter. At the end of the partitioning process, make sure to set the option so it doesn’t format the partition. Please note setting the partition as active doesn’t bother Pioneer!

Because Windows format utility is not able to format your big (32 GB and more) partition, you need to use a third-party FAT32 format utility, and nothing is straighter than FAT 32 Formatter by Tom Thornhill at Ridgecrop Consultants Ltd to download and put to practical use: A simple command of fat32format and you’re done.

If you’re thinking about the cluster size, Microsoft suggests a 32 kB cluster size for drives larger than 32 GB. Don’t worry though, becasue FAT 32 Formatter uses a 32 kB cluster size by default.

More Stupidity

Let’s not forget the CD-UB100 supports three different levels of features depending on the P-series headunit it is connected into:

  1. Basic: showing “USB F###” for folders and “USB T###” for tracks. The mighty DEX-P90RS sadly supports basic level of compatibility when it’s hooked up with CD-UB100!
  2. Medium: showing 8 characters of the info for folder, track, title, etc. Most new heads support a medium level of compatibility when hooked up with CD-UB100.
  3. Complete: showing 64 characters of the info, plus the ability to list. Few newer heads support full compatibility when hooked up with CD-UB100.
Pioneer AVH-P6050DVD and Pioneer CD-UB100

Pioneer AVH-P6050DVD installed on a 2008 Kia Sorento connected to a Pioneer CD-UB100 USB adapter showing “USB T###” for tracks

USB Extension Cable Problem

And this doesn’t end here, the USB cable, its 500 mA limitation, and the fact that no extension cable works, makes it more unbearable. Two of my friends complain about their portable HDDs (Western Digital Passport and Maxtor OneTouch 4 Mini) hooked up with CD-UB100. They say the HDD doesn’t spin when they’re using the USB extension cable supplied with the Pioneer USB adapter. They believe the best condition is to connect the portable HDD directly to the USB connector on the CD-UB100’s body via the high-quality short cable supplied with the HDD by the HDD manufacturer, ignoring Pioneer’s own USB extension cable. Another friend complains about CD-UB100 and his portable HDD which is a Western Digital laptop HDD mounted inside a 2.5” Abacus external enclosure. He says his external enclosure is powered by a Creative CA6110 external power supply, so the enclosure uses Pioneer’s USB cord just to transfer data, and again the headunit fails to recognize the portable hard disk drive when Pioneer’s USB extension cable is used. So the conclusion is to mount CD-UB100 in a place where it’s just a foot away from where you’re gonna put the portable hard disk drive, so you’ll be able to use only the portable HDD’s own cable.

External hard disk drives

IP-Bus: Interactive, but Rather Old and Unintelligent

The whole idea of the IP-Bus (Interactive Pioneer Bus) was something invented (when most cars had no ECU yet) to make the head unit communicate with the CD changer and receive the stereo sound analogly. It’s rather old, and most importantly the sound it transfers is not digital, and just to moan more, my head has a built-in MP3/WMA/AAC decoder, why pay for the decoder inside the CD-UB100 again? They have to invent something new, so the next generation CD-UB100 could read the file from the storage, stream it digitally to a next generation head, and the head unit decodes the streamed media, just like if it was read from the CD inside the head unit’s CD-drive. This way if I have a high-end head, my sound quality would be flawless, mo matter if it’s read from a portable hard disk drive.

9 thoughts on “Hooking Up an HDD to Pioneer Car Audio CD-UB100 USB Adapter

  1. How can pioneer make such fantastic head units…. and then produce this crap on the side?? I have a DEH-P7800MP which boasts a 2×32 character scrolling display and a list function, none of which works with the UB100. I get 8 characters and no list…

  2. Update to whoever is facing the same issue

    Headunit: Pioneer
    Model: AVH-P4250DVD
    Tested: USB Samsung 1.8″
    Size: 250GB
    S/w: FAT 32 Formatter

    Test 1
    – Full format using FAT 32 formatter (250GB)
    – Completed in 4hr+
    – Copied AVI file to test (Failed to load, ‘unplayable’ error displayed)
    – Verified with same file on USB 1GB thumbdrive (Working without issues)

    – Partition 1GB on 250GB Samsung HDD
    – Full format using FAT 32 file system
    – Completed in less than 15 mins
    – Copied AVI file to test (Failed to load, ‘unplayable’ error displayed)
    – Verified with same file on USB 1GB thumbdrive (Working without issues)

    If anyone can share their advise on how to make this 250GB HDD work pls share.


    Gmail: frankietkb@gmail.com

  3. Hello dudes! I have a Pionner DEH-6000UB and I also have a 320GB Western Digital Ext.HD (My Passport Essential model WDBAAA3200ASL).

    The specifications for USB conections are just the same of the model that you were talking about.

    Well I’d like to know if you found out a way to make the pioneer recognizes a Western 320GB HD.

    But there is one important point: this HD has one particular partition (UDF) wich emulates an instalation CD.

    I already tried to format using FAT32, and even making a partition with less than 250GB (i left the rest of the memory unallocated), but it didn’t work.

    Do you guys have any idea of how to make this 320GB HDD work on my pioneer?

    Thank you very much for the attention!


  4. I am in same sitch.
    Wifes 700bt Pioneer works with 16gb thumbs…not with Hitachi 250 Simpledrive RED WINE, or WD My Passport 250gb with blackberry connector.
    After reading this, and a couple other sites with discussion on usb hd’s and usb car stereos…
    I see 2 common probs
    1.) Power
    2.) Partitioning “readability”

    Im going to use a power cord with the Hitachi…(the double usb cord it came with spins it up just fine, without endless clicking, but Pioneer 700BT wont recognize the drive.) I have a dc to ac converter Im going to try just in case it IS a power issue. The Hitachi has a power plug input despite the fact that it is a portable usb hd. (A bad sign really)(maybe meaning its a power hog.)

    The other angle Im gonna take with both the Hitachi and the WD My Passport Essential, is to use the shorter usb cable from the back of the Pioneer. Maybe the usb cable the installers used is just too long.

    And lastly, I keep reading that there is only ONE partition allowed on usb harddrives with some Pioneer head units. So, the “read as CD” partition of the WD, which reads SMARTWARE…and registers a few kbs, maybe the culprit too.
    Gotta figure how to get it off of there.

    The backup file on the Hitachi was easily removed, so no prob with “multi-partition prob” with the Hitachi …. as far as I can tell.

    If all else fails, Im gonna go with 16 gb thumbs, and maybe and old 80gb ipod.

    please, anyone who has a specific drive that they got to work with the Pioneer 700Bt, post the data.

  5. the guy who sold me my p2300 said it had a max capacity of 250gb…i didnt believe him because he didnt know too many of the technical specs but now looking at this i know im in trouble 🙁 this is going to be a bitch.

  6. It’s 2014 and portable HDD units still do not work. I just purchased 3 DDX 370 units with advertisements on their website about compatibility. After installing the units I found out that they do not and will not work with portable HDD’s from tech support. I am currently taking Kenwood to small claims court for a refund and in talks negotiating to get my money back including install time. The advertisements of specifications for hdd have been removed from their website but I have them copied. I just can’t believe that in 2014 car audio multimedia is not capable of interfacing to portable HDD of 1tb or larger? USB flash drives are far inferior in my opinion.

  7. hi, please let me know,
    i have Pioneer DEH-P6950MP

    Does my head unit support CD-UB100 for Complete: showing 64 characters of the info, plus the ability to list.

    Waiting for reply

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