Hi,
RT1050 EVKB change to QSPI boot.
MCUXpresso IDE 10.2.1
QSPI FLASH: IS25WP064A
SDK:2.4.2
Board modify refer to :

change flash config:
const flexspi_nor_config_t qspiflash_config = {
.memConfig =
{
.tag = FLEXSPI_CFG_BLK_TAG,
.version = FLEXSPI_CFG_BLK_VERSION,
.readSampleClkSrc = kFlexSPIReadSampleClk_LoopbackFromDqsPad,
.csHoldTime = 3u,
.csSetupTime = 3u,
// Enable DDR mode, Wordaddassable, Safe configuration, Differential clock
.sflashPadType = kSerialFlash_4Pads,
.serialClkFreq = kFlexSpiSerialClk_100MHz,
.sflashA1Size = 8u * 1024u * 1024u,
.lookupTable =
{
// Read LUTs
FLEXSPI_LUT_SEQ(CMD_SDR, FLEXSPI_1PAD, 0xEB, RADDR_SDR, FLEXSPI_4PAD, 0x18),
FLEXSPI_LUT_SEQ(DUMMY_SDR, FLEXSPI_4PAD, 0x06, READ_SDR, FLEXSPI_4PAD, 0x04),
},
},
.pageSize = 256u,
.sectorSize = 4u * 1024u,
.blockSize = 256u * 1024u,
.isUniformBlockSize = false,
};
Memory Setting:

Debug error:

Awaiting telnet connection to port 3330 ...
GDB nonstop mode enabled
Opening flash driver E:\prj_tools_doc\RT1050\workspace/qspi_flash_emwin_emwin_gui_demo/MIMXRT1050-EVK_IS25WP064A_from_sdk_2.5.0.cfx (already resident)
Sending VECTRESET to run flash driver
Flash variant 'IS25WP064A' detected (8MB = 128*64K at 0x60000000)
Writing 149068 bytes to address 0x60000000 in Flash
ProgramPage (0x60000000, 0x200020E8, 0x4000) status 0x1 - driver reported driver error - EXTSPI driver rc 168 (0xA8)
Closing flash driver E:\prj_tools_doc\RT1050\workspace/qspi_flash_emwin_emwin_gui_demo/MIMXRT1050-EVK_IS25WP064A_from_sdk_2.5.0.cfx
Target error from Commit Flash write: Ef(49): Flash driver operation gave error.
GDB stub (crt_emu_cm_redlink) terminating - GDB protocol problem: Pipe has been closed by GDB.
How to check upper debug error?