I'm trying to flash a u-blox NINA-B406 (nRF52833) using an ST-LINK V2 that has been converted to a J-Link using SEGGER's STLinkReflash firmware. When I select the correct target device (nRF52833_xxAA) in newer J-Link versions, I get the message that the J-Link firmware is only intended for ST devices and debugging/programming this target is not supported.
As a workaround I connect as a generic Cortex-M4, which works well enough to establish an SWD connection and read memory (mem32 0x00000000 4 succeeds and the Cortex-M4 is correctly identified). However, I cannot program the device. erase sometimes succeeds, but both loadfile zephyr.hex and loadbin zephyr.bin 0x00000000 fail with errors such as "Writing target memory failed" or "Unspecified error -1". Is this expected because J-Link only sees a generic Cortex-M4 and therefore lacks the nRF52833 flash loader, or has anyone successfully flashed an nRF52833 using a converted ST-LINK V2?