Estes módulos são geralmente integrados no initrd. Você verificou a integridade do Download do seu Iso e do seu meio de instalação (DVD / USB)? Hier xenial
lsinitramfs /boot/initrd.img-4.4.0-45-generic | grep mmc
lib/modules/4.4.0-45-generic/kernel/drivers/mmc
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/card
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/card/mmc_block.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/card/sdio_uart.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/usdhi6rol0.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/wbsd.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/ushc.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/sdricoh_cs.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/rtsx_pci_sdmmc.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/sdhci.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/sdhci-pltfm.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/tifm_sd.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/cb710-mmc.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/toshsd.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/vub300.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/mtk-sd.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/via-sdmmc.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/sdhci-pci.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/sdhci-acpi.ko
lib/modules/4.4.0-45-generic/kernel/drivers/mmc/host/rtsx_usb_sdmmc.ko
Módulos como mmc_core, mmc_block não são conhecidos no Lubuntu.