I could not find a AM3358EVM here but I did get an AM3359EVM (should be close) and used an XDS510USB PLUS with it. No issues at all.
Could you post the GEL output you get when your connect to the A8? It should look like this:
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CortxA8: Output: **** AM335x 15x15 EVM Initialization is in progress ..........
CortxA8: Output: **** AM335x ALL PLL Config for OPP == OPP100 is in progress .........
CortxA8: Output: Input Clock Read from SYSBOOT[15:14]: 24MHz
CortxA8: Output: **** Going to Bypass...
CortxA8: Output: **** Bypassed, changing values...
CortxA8: Output: **** Locking ARM PLL
CortxA8: Output: **** Core Bypassed
CortxA8: Output: **** Now locking Core...
CortxA8: Output: **** Core locked
CortxA8: Output: **** DDR DPLL Bypassed
CortxA8: Output: **** DDR DPLL Locked
CortxA8: Output: **** PER DPLL Bypassed
CortxA8: Output: **** PER DPLL Locked
CortxA8: Output: **** DISP PLL Config is in progress ..........
CortxA8: Output: **** DISP PLL Config is DONE ..........
CortxA8: Output: **** AM335x ALL ADPLL Config for OPP == OPP100 is Done .........
CortxA8: Output: **** AM335x DDR2 EMIF and PHY configuration is in progress.........
CortxA8: Output: EMIF PRCM is in progress .......
CortxA8: Output: EMIF PRCM Done
CortxA8: Output: DDR PHY Configuration in progress
CortxA8: Output: Waiting for VTP Ready .......
CortxA8: Output: VTP is Ready!
CortxA8: Output: DDR PHY CMD0 Register configuration is in progress .......
CortxA8: Output: DDR PHY CMD1 Register configuration is in progress .......
CortxA8: Output: DDR PHY CMD2 Register configuration is in progress .......
CortxA8: Output: DDR PHY DATA0 Register configuration is in progress .......
CortxA8: Output: DDR PHY DATA1 Register configuration is in progress .......
CortxA8: Output: EMIF Timing register configuration is in progress .......
CortxA8: Output: EMIF Timing register configuration is done .......
CortxA8: Output: DDR PHY Configuration done
CortxA8: Output: **** AM335x DDR2 EMIF and PHY configuration is done ****
CortxA8: Output: **** AM335x 15x15 EVM Initialization is Done ******************