Update, now it went past the linker, however:
# cd /mnt/mmcblk0p4/nexmon/patches/bcm43430a1/7_45_41_46/nexmon
# make clean
# cp /usr/local/lib/libqpdf.so.21 /lib
# mkdir -p /lib/modules/4.4.20-piCore_v7+/build
# make clean
CLEANING
CLEANING DRIVER
make[1]: Entering directory '/lib/modules/4.4.20-piCore_v7+/build'
make[1]: *** No rule to make target 'clean'. Stop.
make[1]: Leaving directory '/lib/modules/4.4.20-piCore_v7+/build'
make: *** [Makefile:229: clean] Error 2
# make
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S E C U R E M O B I L E N E T W O R K I N G
presents:
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The C-based Firmware Patching Framework
!!! WARNING !!!
Our software may damage your hardware and may void your hardware’s
warranty! You use our tools at your own risk and responsibility
STATISTICS DISABLED to enable: delete /mnt/mmcblk0p4/nexmon/DISABLE_STATISTICS
COMPILING src/ioctl.c => obj/ioctl.o (details: log/compiler.log)
COMPILING src/autostart.c => obj/autostart.o (details: log/compiler.log)
COMPILING src/injection.c => obj/injection.o (details: log/compiler.log)
COMPILING src/patch.c => obj/patch.o (details: log/compiler.log)
COMPILING src/version.c => obj/version.o (details: log/compiler.log)
COMPILING src/local_wrapper.c => obj/local_wrapper.o (details: log/compiler.log)
COMPILING src/sendframe.c => obj/sendframe.o (details: log/compiler.log)
COMPILING src/monitormode.c => obj/monitormode.o (details: log/compiler.log)
COPYING UCODE /mnt/mmcblk0p4/nexmon/firmwares/bcm43430a1/7_45_41_46/ucode.bin => gen/ucode.bin
COMPRESSING UCODE gen/ucode.bin => gen/ucode_compressed.bin
GENERATING C FILE gen/ucode_compressed.bin => src/ucode_compressed.c
COMPILING src/ucode_compressed.c => obj/ucode_compressed.o (details: log/compiler.log)
GENERATING C FILE /mnt/mmcblk0p4/nexmon/firmwares/bcm43430a1/7_45_41_46/templateram.bin => src/templateram.c
COMPILING src/templateram.c => obj/templateram.o (details: log/compiler.log)
COMPILING /mnt/mmcblk0p4/nexmon/patches/common/ucode_compression_code.c => obj/ucode_compression_code.o (details: log/compiler.log)
COMPILING /mnt/mmcblk0p4/nexmon/patches/common/wrapper.c => obj/wrapper.o (details: log/compiler.log)
COMPILING /mnt/mmcblk0p4/nexmon/patches/common/argprintf.c => obj/argprintf.o (details: log/compiler.log)
COMPILING /mnt/mmcblk0p4/nexmon/patches/common/helper.c => obj/helper.o (details: log/compiler.log)
COMPILING /mnt/mmcblk0p4/nexmon/patches/common/udptunnel.c => obj/udptunnel.o (details: log/compiler.log)
COMPILING /mnt/mmcblk0p4/nexmon/patches/common/objmem.c => obj/objmem.o (details: log/compiler.log)
COMPILING /mnt/mmcblk0p4/nexmon/patches/common/securitycookie.c => obj/securitycookie.o (details: log/compiler.log)
COMPILING /mnt/mmcblk0p4/nexmon/patches/common/radiotap.c => obj/radiotap.o (details: log/compiler.log)
COMPILING /mnt/mmcblk0p4/nexmon/firmwares/bcm43430a1/7_45_41_46/flashpatches.c => obj/flashpatches.o (details: log/compiler.log)
GENERATING LINKER FILE gen/nexmon.pre => gen/nexmon.ld
GENERATING LINKER FILE gen/nexmon.pre => gen/flashpatches.ld
GENERATING LINKER FILE gen/memory.ld
LINKING OBJECTS => gen/patch.elf (details: log/linker.log, log/linker.err)
GENERATING MAKE FILE gen/nexmon.pre => gen/nexmon.mk
GENERATING MAKE FILE gen/nexmon.pre => gen/flashpatches.mk
APPLYING FLASHPATCHES gen/flashpatches.mk => brcmfmac43430-sdio.bin (details: log/flashpatches.log)
APPLYING PATCHES gen/nexmon.mk => brcmfmac43430-sdio.bin (details: log/patches.log)
BUILDING DRIVER for kernel 4.4 brcmfmac_kernel44/brcmfmac.ko (details: log/driver.log)
make[1]: *** No targets specified and no makefile found. Stop.
make: *** [Makefile:52: brcmfmac.ko] Error 2
I think i am missing some source files, either kernel or wifi modules, or my paths are wrong...
First it was complaining about this folder not existing /lib/modules/4.4.20-piCore_v7+/build then i manually created it, then it continued complaining that there is no Makefile inside.
# cat log/driver.log
make[1]: Entering directory '/lib/modules/4.4.20-piCore_v7+/build'
make[1]: Leaving directory '/lib/modules/4.4.20-piCore_v7+/build'
But i think i have the kernel headers installed...
# su tc -c "tce-load -i -w linux-4.4.y_api_headers"
linux-4.4.y_api_headers is already installed!