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tokens: in 1997 during which it also stayed in the LHS during the entire outburst (Revnivtsev et al. 2000 ; Brocksopp et al. 2001 ). During the 1997 outburst, a similar photon index was observed (Γ = 1.4–1.5; Revnivtsev et al. 2000 ). There are three even earlier detections of X-ray activity of transient sources that can be spatially related to GS 1354–64. During two of these detections the source was in the HSS, while the remaining one caught a source in the LHS (see Tanaka Lewin 1995 , and references therein). In case all observations are related to the same source, this source shows ‘normal’ outbursts with LHS and HSS and so-called ‘failed’ outbursts where it stays in the LHS during the entire outburst. A BHB that is known to show both types of outbursts is H1743−322 (Stiele Yu 2016 , and references therein). Unlike GS 1354–64, H1743−322 shows outbursts quite frequently. Another possibility is that only the ‘failed’ outbursts are related with GS 1354–64 and that the HSS are from a nearby transient source. About 10 X-ray binaries (including neutron stars and black holes) are known that have only been observed during outbursts where they stayed in the LHS (Capitanio et al. 2009 , and references therein). To be certain that GS 1354–64 belongs to the type of BHBs that show ‘normal’ outbursts, we would need to observe an HSS with a modern X-ray satellite that allows us to confirm that the thermal X-ray emission is spatially consistent with the position of GS 1354–64 obtained during the observation of the Comptonized emission during the 2015 outburst. The covariance ratio obtained from the XMM–Newton observation decreases with decreasing energy below 1 keV, while the one obtained for LHS observations of GX 339–4 and Swift J1753.5−0127 increases with decreasing energy (Wilkinson Uttley 2009 ; Stiele Yu 2015 ). The increase of the covariance ratio towards lower energies has been interpreted as a sign of additional disc variability on longer time-scales. Thus, the decrease observed in GS 1354–64 can be either regarded as a sign of missing disc variability on longer time-scales or as a sign of additional variability on short time-scales. For two observations of H1743−322 taken during the 2008 and 2014 ‘failed’ outbursts, we also found covariance ratios that do not show an increase at lower energies. In case of H1743−322, the covariance ratios remained rather flat (Stiele Yu 2016 ). In Stiele Yu ( 2015 ), we investigated the energy dependence of the characteristic frequency of the BLN in PDS and found that for a noise component with a characteristic frequency above 1 Hz the characteristic frequency in the 1–2 keV band is lower than in the 4–8 keV. From the XMM–Newton data of GS 1354–64, we obtain a characteristic frequency of Hz in the 1–2 keV band which is lower than the characteristic frequency of Hz in the 4–8 keV band, although this result is not significant as the errors are big. The sources investigated in Stiele Yu ( 2015 ) showed either an increase of