diff --git a/tcl/interface/ftdi/pipistrello.cfg b/tcl/interface/ftdi/pipistrello.cfg
index b51405a2d..5ee5be5bb 100644
--- a/tcl/interface/ftdi/pipistrello.cfg
+++ b/tcl/interface/ftdi/pipistrello.cfg
@@ -10,4 +10,4 @@ ftdi_layout_init 0x0008 0x000b
 reset_config none
 # this generally works fast: the fpga can handle 30MHz, the spi flash can handle
 # 54MHz with simple read, no dummy cycles, and wait-for-write-completion
-adapter_khz 30000
+adapter_khz 10000