Problems with flash in DA14680-01

我们正在开发一个产品使用DA14680和are hoping to use the built-in flash to boot from and store some data. We have our code working on the DA14681 basic dev kit and now our custom prototype boards based on DA14680 we need to get it working on that platform

I can connect to the DA14680 on our custom board with a J-Link via SWD and can also talk via UART at boot time.

The issue I am having is with the built-in flash, it doesn't seem to work...
- if I upload uartboot.bin via the UART bootloader, the chip hangs. On further investigation I can see that the code is stuck in the Hard Fault handler whilst trying to access the flash (from system_ARMCM0.c function SystemInitPost when calling qspi_automode_init)
- if I change the value of dg_configFLASH_CONNECTED_TO to FLASH_IS_NOT_CONNECTED then the uartboot code will run and I can ask for e.g. "read_chip_info" from cli_programmer, however requesting any of the flash/qspi operations will hang
- if I use the SmartSnippets Toolbox to connect and try and read anything from qspi it will timeout

Has anybody managed to use the flash in the DA14680 - what steps do I need to take that are different from DA14681 with ext flash (as on dev kit)?

I have tried with both SDK 1.0.6 and SDK 1.0.8 - if I switch to SDK 1.0.8 What values should I use for dg_configFLASH_CONNECTED_TO, dg_configFLASH_HEADER_FILE, dg_configFLASH_MANUFACTURER_ID, dg_configFLASH_DEVICE_TYPE, dg_configFLASH_DENSITY

Thanks!