failed to get the flash mapping when trying to download ELF through JTAG

[wzgpeter2017]

it seems the JTAG communication is ok, but when i am trying to download the ELF file into esp32.
it will report the warning info like below. On GDB terminal window, it will report load failure for ELF download as result.
it seems the flash mapping is corrupted by JTAG download process.
how to recover this to setting up the flash mapping correctly?
by telnet?

thank you in advance!

###############################################################
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
Warn : Transport "jtag" was already selected
Info : Configured 2 cores
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : clock speed 2000 kHz
Info : JTAG tap: esp32.cpu0 tap/device found: 0x120034e5 (mfg: 0x272 (Tensilica), part: 0x2003, ver: 0x1)
Info : JTAG tap: esp32.cpu1 tap/device found: 0x120034e5 (mfg: 0x272 (Tensilica), part: 0x2003, ver: 0x1)
Info : esp32: Debug controller 0 was reset.
Info : esp32: Core 0 was reset.
Info : Listening on port 3333 for gdb connections
Info : accepting 'gdb' connection on tcp/3333
Info : Target halted. CPU0: PC=0x400093EA (active)
Info : Target halted. CPU1: PC=0x00000000
Info : cpu0: Target halted, PC=0x40091856, debug_reason=00000001
Warn : Empty flash mapping!
Warn : Failed to get flash mappings (0)!
Info : cpu0: Target halted, PC=0x40091856, debug_reason=00000001
Info : cpu0: Target halted, PC=0x40091856, debug_reason=00000001
Info : Auto-detected flash bank 'esp32.flash' size 4096 KB
Info : Using flash bank 'esp32.flash' size 4096 KB
Info : cpu0: Target halted, PC=0x40091856, debug_reason=00000001
Warn : Empty flash mapping!
Warn : Failed to get flash mappings (0)!
Info : cpu0: Target halted, PC=0x40091856, debug_reason=00000001
Info : Using flash bank 'esp32.irom' size 0 KB
Info : cpu0: Target halted, PC=0x40091856, debug_reason=00000001
Warn : Empty flash mapping!
Warn : Failed to get flash mappings (0)!
Info : cpu0: Target halted, PC=0x40091856, debug_reason=00000001
Info : Using flash bank 'esp32.drom' size 0 KB
Warn : negative reply, retrying
Warn : acknowledgment received, but no packet pending