Background for this problem appears to be a failure to save the re-configured OneClick-Server Webserver memory setting. This is saved to file $SPECROOT/custom/common/config/tomcat-server-config.xml - and may NOT cover a trailing "M" for the -Xmx memory setting.
Here Samples with value "6144" (once you had enabled 64bit Java operation for the CA Spectrum Oneclick server):
-Xmx6144 (is incorrect)
-Xmx6144M (is correct)
The -Xmx parameter will be passed to the loaded Java runtime - to specify the available memory. Doing this with 6144 only results in 6144k of memory which does not allow Java being loaded within Tomcat. The java runtime logfile (jvm.log) will claim about too less memory. For the Windows OC-server implementation the startup file is ./tomcat/bin/OneClickService.conf - which is looking fine covering the "M".
The upgrade processing will not take the OneClickService.conf file/content - as this file is rebuild per each OC-server reconfiguration step. So the processing will take Xmx parameter from tomcat-server-config.xml - which is incorrect.
Editing tomcat-server-config.xml parameter to correct "-Xmx6144M" will allow successful upgrade processing.