You need to install the plain version.
Hi Phil,
I have the Chord Mojo DAC which runs from battery, and unfortunately I am having the same issues as you’re having. When I turn off the Mojo, next time I turn it on it will work, but the 2nd time round the USBridge no longer reports the DAC to Roon. The OS still sees it in aplay -L and even lsusb, but for some reason the usb controller seem to lock up.
Trying to reboot the USBridge at this stage hangs, and I am often forced to just power cycle it to get back to listening to music. I think @allo should make it a high priority to get a later kernel version working with the Sparky board, which would mean we’ll have more options wrt the OS we can run(Ropiee ie).
I must admit I have been quite busy, so I haven’t spent a lot of time diagnosing the USB issues on the latest versions of DIetpi, but I will let you know if I find anything useful.
PS. The issues I am seeing is in Dietpie 6.8, I am now upgrading to 6.9
As a point of reference I use a Chord Mojo with my Allo USBridge and have no problems powering the Mojo off and on with Roon. I leave the USBridge on 24/7 and only power on the Mojo when needed. The Mojo is detected by Roon every time without issue. I am using v6.9 of the Allo GUI. The USBridge is connected via Ethernet and I am using the stock Allo power adapter. It just works.
That is great to hear! I will try with Dietpi 6.9, and hopefully it will resolve the issues I am seeing.
Unfortunately mine is on 6.9 and it is worse now than it was.
I am frustrated with @allo.com here as they should have a stable unit.
My unit was fine last night, but this morning no usb connection and a power cycle.
Thanks for the link @Fernando_Pereira. I’ve been trying to follow these instructions, but it’s useless.
My situation is like this:
On a Mac, trying to flash USBridge internal emmc card with plain (non-Allo) DietPi. It’s not an issue to open the case or not. I don’t understand if I need to follow the ‘write image to SD card with Etcher’ instructions from DietPi website, or not. If I copy just the downloaded DietPi 7z file to the SD card and insert it to the USBridge according to the Allo instructions, the USBridge starts from the internal emmc, so I cannot write anything to that, right?
Do I need to boot Sparky from emmc or from SD?
Can I use Etcher to burn image directly to emmc card (inserted in the supplied emmc reader)?
Any help from fellow Roon/USBridge users will be appreciated, as I’ve spent over a week trying to get this to work, thanks.
Yes – this is exactly what you will nee to do. Unzip the 7z file and flash the .img file to the eMMC via Etcher.
Thanks, Rene. I’ll try it.
Godspeed! 
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Indeed it worked, thank you so much! I had actually attempted that before, but had trouble with card readers not reading emmc, which made me wrongly assume emmc is not readable on the Mac. After your encouragement, an external reader plus adapter finally worked, and DietPi is now working on USBridge!
To optimise for audio, I set CPU Governor to performance and Max Freq 720 MHz (as Roon does not see the USBridge if set to Powersave).
Having already listened earlier on to plain (non-Allo) DietPi booted from external mSD card, I can confirm your and @Fernando_Pereira’s findings that it sounds better (clearer, better instrument separation, better front-to-back stereo image).
Thank you @RBM, @Fernando_Pereira, and to all this wonderful community!
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In case it’s useful to anybody else, I tried @Fernando_Pereira’s earlier suggestion to:
apt remove alsa-utils
That worked, no more amixer trouble on reboot and Roon Bridge works perfectly. It would be great if Roon Bridge did not bring in all that unnecessary ALSA utility cruft.
It didn’t work in my case. USBridge disappeared from Roon (perhaps because I have no other audio applications in DietPi, except Roon). I then did:
dietpi-software reinstall 121
and all is well.
Similar complaints to you, Wouter – USBridge to a Rotel RC1590; sometimes it’s there, sometimes it’s not. Have to power cycle to make it reappear. Which is a shame, because I really love the way it sounds.
Haven’t investigated in the OS, but may do so, to see if same results as you.
Note that I have the Rotel set to turn itself off after 5 hours of idle time.
hi, when you turn off the mojo you first stop the music in roon? or you just turn off mojo suddenly? because I realized that if i turn off mojo without pausing the music the system stop recognizing mojo and then i have to reboot.
Hi Adrian,
Thanks for the suggestion, but I do pause the music first before turning off the mojo, and I am having the same issue even on Dietpi 6.9.
It looks like the USB subsystem is having issues, as I can not disable the device at that stage, and it also causes soft reboots to fail.
Hi gents I don’t know if any of you have seen this post, it may or may not help: DietPi + Allo Web GUI: Now available:
possibility: Dac alone power off during Music play, this case USBridge USB port locking with player.
you can do SSH login and nano /DietPi/uEnv.txt aotg.urb_fix=0
note : edit this only for ROON, Roon+ HQplayer this parameter need to set 1
You may already have solved this, but let me know if you still have questions or concerns about rehashing your USBridge with the latest DietPi. It was not terribly difficult and still sounds great after the update. 
Has anyone tried powering the Usbridge by a powerbank? Maximum battery amperage I find is 2.4A and Usbridge spec is 3A. I keep CPU Governor at Max Freq 720 MHz, so power requirements might be lower? Any experience? I wouldn’t want to damage this wonderful endpoint, for sure.
Btw, I’ve tried a powerbank (TP-LINK 5200) to power Sparky (with Allo PSU for Usbridge) and think it sounds purer, similar to less jitter. So I’d like to try it on Usbridge,too, hence the question.
Accordign to the description of the Allo USBridge, the Sparky is the “power hungry one” and it is possible to power the two boards separately removing the jumper.
The Sparky can be supplied with the stock SMPS, and the USB card with the power bank.
Power first the USB card, than the Sparky board.
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Thanks but that’s not correct.
According to Allo, “Please note that you can feed the Sparky separately with one PSU (5V / 2.0A) and USbridge HAT (5V / 100ma + whatever your DAC needs).”
@RBM’s configuration: “The USBridge is powered by a 5V/3A Sbooster LPSU; the Sparky is powered separately over USB by an old iPad PSU.“
Usbridge power requirements:
microUSB (Sparky) 5V/1.8A
DC (USBridge) 5V/3A