I am testing on a GBA SP (ags-001) handhled with an Omega flash DE cartridge and test suite r88. I tried even loading it as a direct boot cart.
No matter what, the Memory tests show 1514/1552, even if it is the first thing I boot. Only the DMA0 tests under the out-of-bounds category pass, everything else is failing. Running other tests doesn't seem to be affecting this.