No debug output when loading ath10k

Hello!
I am trying to run QCA9988 with ath10k. Now I get this output to the console:

root@OpenWrt:/# rmmod ath10k_pci
root@OpenWrt:/# rmmod ath10k_core
root@OpenWrt:/# modprobe ath10k_core debug_mask=0xffffffff
root@OpenWrt:/# modprobe ath10k_pci
[ 5138.244245] ath10k_pci 0000:00:00.0: pci irq legacy oper_irq_mode 1 irq_mode 0 reset_mode 0
[ 5139.854652] ath10k_pci 0000:00:00.0: qca9984/qca9994 hw1.0 target 0x01000000 chip_id 0x00000000 sub 168c:cafe
[ 5139.865062] ath10k_pci 0000:00:00.0: kconfig debug 1 debugfs 1 tracing 0 dfs 1 testmode 0
[ 5139.886145] ath10k_pci 0000:00:00.0: firmware ver 10.4-3.9.0.2-00131 api 5 features no-p2p,mfp,peer-flow-ctrl,btcoex-param,allows-mesh-bcast,no-ps,peer-fixed-rate crc32 23bd9e43
[ 5142.181394] ath10k_pci 0000:00:00.0: failed to fetch board data for bus=pci,vendor=168c,device=0046,subsystem-vendor=168c,subsystem-device=cafe from ath10k/QCA9984/hw1.0/board-2.bin
[ 5142.431487] ath10k_pci 0000:00:00.0: failed to fetch board-2.bin or board.bin from ath10k/QCA9984/hw1.0
[ 5142.441342] ath10k_pci 0000:00:00.0: failed to fetch board file: -12
[ 5142.465190] ath10k_pci 0000:00:00.0: could not probe fw (-12)

I can't understand why there is no debug output, despite the debug_mask I specified. What am I missing?