Delete .elf file and clean hole projekt.
Build new.
11:33:35 Build of configuration Debug for project Pico_Blink
scons.bat -j6
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...

scons: warning: you do not seem to have the pywin32 extensions installed;

parallel (-j) builds may not work reliably with open Python files.

File "C:RT-ThreadStudioplatformenv_releasedenvtoolsPython27Scriptsscons.py", line 204, in <module>
scons: building associated VariantDir targets: build
CC buildapplicationsmain.o
CC builddriversboard.o
CC builddriversdrv_gpio.o
CC builddriversdrv_uart.o
CC buildkernelcomponentsdriversmiscpin.o
CC buildkernelcomponentsdriversrtcrtc.o
CC buildkernelcomponentsdriversserialserial.o
CC buildkernelcomponentsdriverssrccompletion.o
CC buildkernelcomponentsdriverssrcdataqueue.o
CC buildkernelcomponentsdriverssrcpipe.o
CC buildkernelcomponentsdriverssrcringblk_buf.o
CC buildkernelcomponentsdriverssrcringbuffer.o
CC buildkernelcomponentsdriverssrcwaitqueue.o
CC buildkernelcomponentsdriverssrcworkqueue.o
CC buildkernelcomponentsfinshcmd.o
CC buildkernelcomponentsfinshmsh.o
CC buildkernelcomponentsfinshshell.o
CC buildkernelcomponentslibccompilerscommontime.o
CC buildkernelcomponentslibccompilersnewlibminilib.o
CC buildkernelcomponentsutilitiesulogbackendconsole_be.o
CC buildkernelcomponentsutilitiesulogulog.o
CC buildkernellibcpuarmcommonbacktrace.o
CC buildkernellibcpuarmcommondiv0.o
CC buildkernellibcpuarmcommonshowmem.o
AS buildkernellibcpuarmcortex-m0context_gcc.o
CC buildkernellibcpuarmcortex-m0cpuport.o
CC buildkernelsrcclock.o
CC buildkernelsrccomponents.o
CC buildkernelsrcdevice.o
CC buildkernelsrcidle.o
CC buildkernelsrcipc.o
CC buildkernelsrcirq.o
CC buildkernelsrckservice.o
CC buildkernelsrcmem.o
CC buildkernelsrcmempool.o
CC buildkernelsrcobject.o
CC buildkernelsrcscheduler.o
CC buildkernelsrcthread.o
CC buildkernelsrctimer.o
AS buildlibrariesgeneratedbs2_default_padded_checksummed.o
CC buildlibrariespico-sdksrccommonpico_synccritical_section.o
CC buildlibrariespico-sdksrccommonpico_synclock_core.o
CC buildlibrariespico-sdksrccommonpico_syncmutex.o
CC buildlibrariespico-sdksrccommonpico_syncsem.o
CC buildlibrariespico-sdksrccommonpico_timetime.o
CC buildlibrariespico-sdksrccommonpico_timetimeout_helper.o
CC buildlibrariespico-sdksrccommonpico_utildatetime.o
CC buildlibrariespico-sdksrccommonpico_utilpheap.o
CC buildlibrariespico-sdksrccommonpico_utilqueue.o
CC buildlibrariespico-sdksrcrp2_commonhardware_claimclaim.o
CC buildlibrariespico-sdksrcrp2_commonhardware_clocksclocks.o
AS buildlibrariespico-sdksrcrp2_commonhardware_dividerdivider.o
CC buildlibrariespico-sdksrcrp2_commonhardware_gpiogpio.o
CC buildlibrariespico-sdksrcrp2_commonhardware_irqirq.o
AS buildlibrariespico-sdksrcrp2_commonhardware_irqirq_handler_chain.o
CC buildlibrariespico-sdksrcrp2_commonhardware_pllpll.o
CC buildlibrariespico-sdksrcrp2_commonhardware_syncsync.o
CC buildlibrariespico-sdksrcrp2_commonhardware_timertimer.o
CC buildlibrariespico-sdksrcrp2_commonhardware_uartuart.o
CC buildlibrariespico-sdksrcrp2_commonhardware_vregvreg.o
CC buildlibrariespico-sdksrcrp2_commonhardware_watchdogwatchdog.o
CC buildlibrariespico-sdksrcrp2_commonhardware_xoscxosc.o
AS buildlibrariespico-sdksrcrp2_commonpico_bit_opsbit_ops_aeabi.o
CC buildlibrariespico-sdksrcrp2_commonpico_bootrombootrom.o
AS buildlibrariespico-sdksrcrp2_commonpico_dividerdivider.o
AS buildlibrariespico-sdksrcrp2_commonpico_doubledouble_aeabi.o
CC buildlibrariespico-sdksrcrp2_commonpico_doubledouble_init_rom.o
CC buildlibrariespico-sdksrcrp2_commonpico_doubledouble_math.o
AS buildlibrariespico-sdksrcrp2_commonpico_doubledouble_v1_rom_shim.o
AS buildlibrariespico-sdksrcrp2_commonpico_floatfloat_aeabi.o
CC buildlibrariespico-sdksrcrp2_commonpico_floatfloat_init_rom.o
CC buildlibrariespico-sdksrcrp2_commonpico_floatfloat_math.o
AS buildlibrariespico-sdksrcrp2_commonpico_floatfloat_v1_rom_shim.o
AS buildlibrariespico-sdksrcrp2_commonpico_int64_opspico_int64_ops_aeabi.o
CC buildlibrariespico-sdksrcrp2_commonpico_mallocpico_malloc.o
AS buildlibrariespico-sdksrcrp2_commonpico_mem_opsmem_ops_aeabi.o
CC buildlibrariespico-sdksrcrp2_commonpico_platformplatform.o
CC buildlibrariespico-sdksrcrp2_commonpico_printfprintf.o
CC buildlibrariespico-sdksrcrp2_commonpico_runtimeruntime.o
CC buildlibrariespico-sdksrcrp2_commonpico_standard_linkbinary_info.o
AS buildlibrariespico-sdksrcrp2_commonpico_standard_linkcrt0.o
CXX buildlibrariespico-sdksrcrp2_commonpico_standard_linknew_delete.o
CC buildlibrariespico-sdksrcrp2_commonpico_stdiostdio.o
CC buildlibrariespico-sdksrcrp2_commonpico_stdio_uartstdio_uart.o
CC buildlibrariespico-sdksrcrp2_commonpico_stdlibstdlib.o
LINK rtthread-pico.elf
arm-none-eabi-objcopy -O binary rtthread-pico.elf rtthread.bin
arm-none-eabi-size rtthread-pico.elf
text data bss dec hex filename
81104 0 84172 165276 2859c rtthread-pico.elf
C:Workspace_RT_ThreadPico_Blinklibrariesgeneratedelf2uf2.exe rtthread-pico.elf rtthread-pico.uf2
scons: done building targets.

11:33:41 Build Finished. 0 errors, 0 warnings. (took 5s.447ms)

• copy rtthread-pico.uf2 to device -> no communication on RS232 no blinking!

Why