Solution : https://service.sap.com/sap/support/notes/172143 (SAP Service marketplace login required)
Key words : 
4 etq232 rfc login succeeded  4 etq233 calling function module, upgrade phase pcon_<rel>   starting distribution, r3up error message  r3up> error, @new_dbtype = 'tinyint'                     sap_change_datatype @ddtype = 'prec', upgrade phase xtern_cnv   moving nametabs, upgrade phase mvntab_bas   moving nametabs, @new_dbtype = 'decimal'                     sap_repair_nullable_initial                     sap_unpad_all                     sap_droproc, command  drop proc sap_upg_repair_int1_precin, <sid>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  2eegt131 invalid operation, r3up message  severe error
Related Notes : 
       
| 388189 | Enhancements to upgrade to 4.6C SR2 MSSQL Server | 
| 329195 | Additional info on upgrading to 4.6C SR1 MSSQL server | 
| 201075 | Additions upgrading to 4.6C ... MSSQL Server | 
| 150540 | Add. Info: Upgrading to 3.1H,3.1I SQL Server 7.0 |