There are several instances in the error checking and handling code inside MMCSD_xferStatusPollingFxn() where "error interrupt bits" are accessed in the MMC_CTLCFG_NORMAL_INTR_STS register (rather than in the MMC_CTLCFG_ERROR_INTR_STS register, basically mixing up bit definitions and register names. This results in error bits not getting cleared as intended.