Solution : https://service.sap.com/sap/support/notes/534627 (SAP Service marketplace login required)
Key words : 
service marketplace bw front-end patches, 0b/binary patches/sap gui, 0b front-end patch 8 introduces, downloading bw front-end patches, select bw sap bw/sap 2, 0b front-end patches, bw front-end programs, 0b front-end patch 17, 0b front-end patch, sap download area appears
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| 309281 | BW 2.0B frontend installation of patches | 
| 197460 | BW Frontend Checktool sapbexc.xla | 
| 96885 | Downloading front end patches |