Rolling back GNURadio for old USRP firmware?

I borrowed a couple USRP-2920s from a colleague, and I promised that I
would not break them during my use.

After upgrading from GNURadio3.2 to 3.4.2 with UHD support by using
Marcus’s install script, I got the following error trying to run

RuntimeError: RuntimeError:
Please update the firmware and FPGA images for your device.
See the application notes for USRP2/N-Series for instructions.
Expected FPGA compatibility number 8, but got 7:
The FPGA build is not compatible with the host code build.

Since I promised that I wouldn’t change my colleague’s setting, I was
wondering if there’s any easy way for me to roll back my GNURadio
install so that I can use his existing firmware #7.

Alternatively, I am willing to try upgrading the firmware to #8 and then
roll that back to #7 if that’s easier.

Any help is appreciated, TIA,