Solving Error: Unknown flash device: An OpenOCD Upgrade for Pi Pico / Xiao and other RP2040 Boards

RE: Solving Error: Unknown flash device: An OpenOCD Upgrade for Pi Pico / Xiao and other RP2040 Boards

Coconut1 — Sat, 14 Feb 2026 20:56:10 GMT

I had the exact same problem as described above. Bought 4 cheap Pico Boards online and encountered the connection problem when starting to debug.
With a closer look at the board I could see that there is no 10-pin voltage regulator but a unknown 6-pin and additionally a 2MB Flash 'BY25Q16ES' from
the chines manufacture BYTe Semiconductor. So I was sure, these boards where counterfeit PICOs.
The error message then was
--> Error: Unknown flash device (ID 0x00154068)

The by far easiest way to solve this, is to open the openocd.exe in a text editor and search for the entries of the table shown above.
The 10 values of each line there will be interpreted as:
name, read_cmd, qread_cmd, pprog_cmd, erase_cmd, chip_erase_cmd, device_id, pagesize, sectorsize, size_in_bytes

Now since I knew my Flash device, I download its data sheet and checked for the read/write/prog/erase commands and found that there already is an almost identical device
given with a slightly different device ID 0x001540C8. The rest was easy.
Seraching in a text editor (e.g. np++ in HEX-mode) for the byte-sequence "C8 40 15 00" and finding a "03 00 02 D8 C7 00 00 00" next to it, indicating the correct file position.
Now I changed the "C8" to "68" and saved the modified file openocd.exe.

And it worked!!! The debugger now starts smoothly and every thing is fine ... now after 30+ hours of serching and trying.

RE: Solving Error: Unknown flash device: An OpenOCD Upgrade for Pi Pico / Xiao and other RP2040 Boards

Coconut1 — Sat, 14 Feb 2026 20:44:54 GMT

The by far easiest way to solve this, is to open the openocd.exe in a text editor and search for the entries of the table shown above.
The 10 values of each line there will be interpreted as:
name, read_cmd, qread_cmd, pprog_cmd, erase_cmd, chip_erase_cmd, device_id, pagesize, sectorsize, size_in_bytes

Now since I knew my Flash device I download its data sheet and checked for the read/write/prog/erase commands and found that there already is an almost identical device
"st m25pe16" given with a slightly different device ID 0x00158020.
The rest was easy. Seraching in a text editor (e.g. np++ in HEX-mode) for the byte-sequence “20 80 15 00” and finding a “03 00 02 D8 C7 00 00 00” next to it, indicating the correct file position. Now I changed the "20 80" to 68 40" and saved the modified file.

And viola … it worked. The debugger now started smoothly. Every thing is fine now … after 50+ hours of serching and trying.

RE: Solving Error: Unknown flash device: An OpenOCD Upgrade for Pi Pico / Xiao and other RP2040 Boards

fischp — Thu, 28 Aug 2025 23:36:28 GMT

Hi, I just bought several RP Picos and I'm having an issue getting my openocd to work with it. I'm using vscode and the pico extension on my mac. I'll paste a copy of the debug session's output below, but basically, it doesn't recognize my flash ID. I forked your openocd code and I'd like to add my chip's details into the spi.c file. Sadly, I don't know what to put into the file other than the chip's id. How can I find this or can you please help/guide me?

Here's the debug output:

[2025-08-28T23:18:55.821Z] SERVER CONSOLE DEBUG: onBackendConnect: gdb-server session connected. You can switch to "DEBUG CONSOLE" to see GDB interactions.
/Users/fischp/.pico-sdk/openocd/0.12.0+dev/openocd.exe -c "gdb_port 50000" -c "tcl_port 50001" -c "telnet_port 50002" -s /Users/fischp/.pico-sdk/openocd/0.12.0+dev/scripts -f /Users/fischp/.vscode/extensions/marus25.cortex-debug-1.12.1/support/openocd-helpers.tcl -f interface/cmsis-dap.cfg -f target/rp2040.cfg -c "adapter speed 5000"
Open On-Chip Debugger 0.12.0+dev (2025-07-17-12:44)
Licensed under GNU GPL v2
For bug reports, read
openocd.org/.../bugs.html
DEPRECATED! use 'gdb port', not 'gdb_port'
DEPRECATED! use 'tcl port' not 'tcl_port'
DEPRECATED! use 'telnet port', not 'telnet_port'
CDLiveWatchSetup
Info : [rp2040.core0] Hardware thread awareness created
Info : [rp2040.core1] Hardware thread awareness created
adapter speed: 5000 kHz
Info : Listening on port 50001 for tcl connections
Info : Listening on port 50002 for telnet connections
Info : Using CMSIS-DAPv2 interface with VID:PID=0x2e8a:0x000c, serial=E663AC91D37B8939
Info : CMSIS-DAP: SWD supported
Info : CMSIS-DAP: Atomic commands supported
Info : CMSIS-DAP: Test domain timer supported
Info : CMSIS-DAP: FW Version = 2.0.0
Info : CMSIS-DAP: Interface Initialised (SWD)
Info : SWCLK/TCK = 0 SWDIO/TMS = 0 TDI = 0 TDO = 0 nTRST = 0 nRESET = 0
Info : CMSIS-DAP: Interface ready
Info : clock speed 5000 kHz
Info : SWD DPIDR 0x0bc12477, DLPIDR 0x00000001
Info : SWD DPIDR 0x0bc12477, DLPIDR 0x10000001
Info : [rp2040.core0] Cortex-M0+ r0p1 processor detected
Info : [rp2040.core0] target has 4 breakpoints, 2 watchpoints
Info : [rp2040.core0] Examination succeed
Info : [rp2040.core1] Cortex-M0+ r0p1 processor detected
Info : [rp2040.core1] target has 4 breakpoints, 2 watchpoints
Info : [rp2040.core1] Examination succeed
Info : [rp2040.core0] starting gdb server on 50000
Info : Listening on port 50000 for gdb connections
Info : accepting 'gdb' connection on tcp/50000
Info : no SDFP found
Error: RP2040 rev 2, QSPI Flash id = 0x154068 not recognised
Error: auto_probe failed
Error: Connect failed. Consider setting up a gdb-attach event for the target to prepare target for GDB connect, or use 'gdb_memory_map disable'.
Error: attempted 'gdb' connection rejected
shutdown command invoked

RE: Solving Error: Unknown flash device: An OpenOCD Upgrade for Pi Pico / Xiao and other RP2040 Boards

Jan Cumps — Sun, 19 May 2024 06:47:07 GMT

If you used the Windows Installer for the Pico C SDK, the easiest way to update its OPENOCD installation is to:

back up SDK_ROOT/openocd/openocd.exe
copy shabaz' ZIPFILE/openocd/src/openocd.exe to SDK_ROOT/openocd/openocd.exe
back up SDK_ROOT/openocd/scripts/target/rp2040.cfg
copy ZIPFILE/openocd/tcl/target/rp2040.cfg to SDK_ROOT/openocd/scripts/target/rp2040.cfg

Tested with a Pico RP2040 and XIAO RP2040, and SDK version 1.5.1.
Expected to work with SDK 1.5.0 too, as it uses the exact same OPENOCD setup as 1.5.1.