We also have Echo 3G, but it didn't work. We have
error:
[ 1326.803139] firmware: requesting ea/echo3g_dsp.fw
[ 1326.825403] firmware: requesting ea/3g_asic.fw
[ 1327.995014] wait_handshake(): Timeout waiting for DSP
[ 1328.017190] wait_handshake(): Timeout waiting for DSP
[ 1328.033190] ACPI: PCI interrupt for device 0000:05:09.0 disabled
[ 1328.033190] Echoaudio Echo3G: probe of 0000:05:09.0 failed with error -5
having used echo cards for the past half decade, ive seen this error a number of times .
on about 30% of fresh installs espescially when going minimalist/DIY ie LFS
but not in the last year or so. try symlinking /lib/firmware to /usr/lib/firmware and make
sure the file is there, the error is a bit obtuse