Solution : https://service.sap.com/sap/support/notes/1095885 (SAP Service marketplace login required)
Key words :
upgrade gui----------------------< c5018355 jan/04/08 >---------------------------phase drop_shadow_schema_os4as, /usr/sap/<sid>/upg/abap, shadow instance userare transferred, java/dual-stack upgrade, chgown <sid>ofr, double-stack systems, experience long runtimes, theuser <sid><nn>, user <sid>ofr, java upgrade program
Related Notes :
| 1665188 | IBM i: Upgrade causes data loss in productive database |
| 1119188 | iSeries: Upgrade modification of file /usr/sap/sapservices |