The TS-7500 is based on a Cavium CNS2132 (aka Star Semi STR8132) which contains a Faraday FA-526 core and as a ARMv4 it has NO thumb or thumb interworking support. Most major linux distributions have decided to make ARMv4T (not ARMv4) the minimum supported architecture for their packages so OE is the best way to roll your own. see the Debian discussion. That is why you need to use openembedded.
If you need to build your own kernel See https://github.com/embeddedarm/linux-3.4-ts75xx/network
These flags let you build code with almost any gcc-arm toolkit. -march=armv4 -mno-thumb-interwork -marm -mfloat-abi=soft