error that we have received when trying to set the new system software as startup was:
startup system-software s5700li-v200r001c00spc300.cc
Error: Upgrade basic-bootrom failed.Software does not match this device.
Error: Failed in upgrading bootrom, next step is copying file. Continue?[Y/N]:Y
Error: The file is not supported by the device.
Info: Failed in setting the software for booting system.
S5700-28X-PWR-LI-AC is new on the market and was designed to support new features available only on the newer versions. So actually the first system-software and only available for this model is V200R002C00SPC100 and V200R003C00SPC300.