Dear sir,
About "gUpgradeImageOnCurrentDevice_d", I couldn't understand what it mean. Could you please describe it?
About the alternative method you suggested, I can't use test tool "OTA updates" to update server, right?

If I build my PC application with UART interface to update server,
do I need modify the code of server beside enabling gUpgradeImageOnCurrentDevice_d?
Finally, how I to build my PC application? Do you teach me and what document and sample code could be studied?
Thanks.
BR,
Sean