# USRP2 and UHD 3.8.3

**URL:** <https://www.ruby-forum.com/t/usrp2-and-uhd-3-8-3/241689>\
**Category:** GNU Radio\
**Created:** [April 23, 2015, 7:13pm UTC](https://www.ruby-forum.com/t/usrp2-and-uhd-3-8-3/241689 "2015-04-23T19:13:43Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [April 23, 2015, 7:13pm UTC](https://www.ruby-forum.com/t/usrp2-and-uhd-3-8-3/241689/1 "2015-04-23T19:13:43Z")

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Dear USRP2 users,

(_Note:_ this does not affect N2x0, or any other device! Only USRP2,  
with the SD-Card).

The latest release (3.8.3) has an issue where UHD won’t let you use  
USRP2s. Apologies for missing that during testing and RC phases. Latest  
maint (and master) contain a fix for this, and future releases will also  
work.

If you need to run USRP 2 with a stable release, we recommend 3.8.2,  
although the USRP2 code (both host- and FPGA-side) has not changed in a  
long time, so older versions will also work.

So, what happened? Our latest release actually had some changes for  
N2x0, mostly related to UBX fixes. As a consequence, we updated the N2x0  
FPGA images, and increased the compat number. On USRP2, nothing was  
changed at all, but due to shared host driver code, UHD is looking for  
the same compat number on both devices. Since we didn’t touch USRP2  
specifically, it fell through in our testing.

This fix simply provides separate compat numbers for USRP2 and N2x0. The  
actual FPGA image for USRP2 never changed, so you don’t need to burn the  
SD card for this. If you already did, that’s also fine – the current  
FPGA images for USRP2 are legit.

Cheers,

Martin

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**Author:** ![pytlik](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/779978/32.png) [@pytlik](https://www.ruby-forum.com/u/pytlik)\
**Post date:** [April 24, 2015, 1:14pm UTC](https://www.ruby-forum.com/t/usrp2-and-uhd-3-8-3/241689/2 "2015-04-24T13:14:41Z")

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Jonathon,  
The source code for both USRP2 and N210 was updated at the same commit  
with the new FPGA compat number  
(78eab419fdcdc18f4da8fd33f267af6c4d0494f6).  
Hoever because nothing changed _functionally_ on USRP2 someone forgot to  
re-build USRP2 images for inclusion in the updated binary image package.  
You are not affected because you build your FPGA from sourceit only  
affects (typical) users who get pre-built FPGA’s from Ettus.

-Ian

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**Author:** ![pytlik](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/779978/32.png) [@pytlik](https://www.ruby-forum.com/u/pytlik)\
**Post date:** [April 24, 2015, 5:57pm UTC](https://www.ruby-forum.com/t/usrp2-and-uhd-3-8-3/241689/3 "2015-04-24T17:57:49Z")

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Is a patch available to fix the problem?