Issue flashing eMMC on RPi CM4: mass storage device not showing

[pojithakarunathilake99]

Describe the bug

Hi,

I am currently trying to flash the eMMC on a RPI CM4 mounted in a Raspberry PI CM4 io Board . I am stuck with the USB mass storage device not come up or not showing . after flashed Green LED is blinking.

I have followed the correct step as the documentation

Steps to reproduce the behaviour

flashing cm4

Device(s)

Raspberry Pi CM4

Compute Module IO board.

Raspberry PI Compute Module 4 IO Board

RPIBOOT logs

sudo ./rpiboot -d mass-storage-gadget64
RPIBOOT: build-date 2025/09/18 pkg-version local 48821f0

Please fit the EMMC_DISABLE / nRPIBOOT jumper before connecting the power and USB cables to the target device.
If the device fails to connect then please see https://rpltd.co/rpiboot for debugging tips.

Loading: mass-storage-gadget64/bootfiles.bin
Using mass-storage-gadget64/bootfiles.bin
Waiting for BCM2835/6/7/2711/2712...

Sending bootcode.bin
Successful read 4 bytes
Waiting for BCM2835/6/7/2711/2712...

Second stage boot server
File read: mcb.bin
File read: memsys00.bin
File read: memsys01.bin
File read: memsys02.bin
File read: memsys03.bin
File read: memsys04.bin
File read: memsys05.bin
File read: memsys06.bin
File read: memsys07.bin
File read: memsys08.bin
File read: bootmain
Loading: mass-storage-gadget64/config.txt
File read: config.txt
Loading: mass-storage-gadget64/boot.img
File read: boot.img
Second stage boot server done

Kernel logs

[ 3029.410360] usb 1-2.1: new high-speed USB device number 44 using xhci_hcd
[ 3029.532197] usb 1-2.1: config index 0 descriptor too short (expected 55, got 32)
[ 3029.548197] usb 1-2.1: New USB device found, idVendor=0a5c, idProduct=2711, bcdDevice= 0.00
[ 3029.548203] usb 1-2.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 3029.548206] usb 1-2.1: Product: BCM2711 Boot
[ 3029.548210] usb 1-2.1: Manufacturer: Broadcom
[ 3029.548213] usb 1-2.1: SerialNumber: 57234ebe
[ 3031.756050] usb 1-2.1: USB disconnect, device number 44
[ 3032.994337] usb 1-2.1: new high-speed USB device number 45 using xhci_hcd
[ 3033.133953] usb 1-2.1: New USB device found, idVendor=0a5c, idProduct=2711, bcdDevice= 0.00
[ 3033.133960] usb 1-2.1: New USB device strings: Mfr=1, Product=2, SerialNumber=4
[ 3033.133964] usb 1-2.1: Product: BCM2711 Boot
[ 3033.133968] usb 1-2.1: Manufacturer: Broadcom
[ 3033.133971] usb 1-2.1: SerialNumber: 57234ebe
[ 3037.899628] usb 1-2.1: USB disconnect, device number 45
[ 3045.774221] usb 1-2.1: new high-speed USB device number 46 using xhci_hcd
[ 3045.919076] usb 1-2.1: New USB device found, idVendor=0a5c, idProduct=0104, bcdDevice= 1.00
[ 3045.919083] usb 1-2.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 3045.919087] usb 1-2.1: Product: Raspberry Pi multi-function USB device
[ 3045.919091] usb 1-2.1: Manufacturer: Raspberry Pi
[ 3045.919094] usb 1-2.1: SerialNumber: 1000000057234ebe
[ 3045.950154] cdc_acm 1-2.1:1.0: ttyACM0: USB ACM device

Device UART logs

{
"USER_SERIAL_NUM" : "57234ebe",
"MAC_ADDR" : "2c:cf:67:fd:c3:93",
"CUSTOMER_KEY_HASH" : "0000000000000000000000000000000000000000000000000000000000000000",
"BOOT_ROM" : "000048b0",
"BOARD_ATTR" : "c0000000",
"USER_BOARDREV" : "d03141",
"JTAG_LOCKED" : "0",
"ADVANCED_BOOT" : "0000e8e8"
}

[nbuchwitz]

Serial console of the mass-storage-gadget appears in your logs (ttyACM0), so it is booting. You can connect via picocom or other tools and check in the booted Linux if any storage device is detected. Just to be sure, this is a CM4 with eMMC and not a lite?

[pojithakarunathilake99]

yes it is 32GB emmc

[pojithakarunathilake99]

Serial console of the mass-storage-gadget appears in your logs (ttyACM0), so it is booting. You can connect via picocom or other tools and check in the booted Linux if any storage device is detected. Just to be sure, this is a CM4 with eMMC and not a lite? for the information
dmesg | grep mmc
[ 2.711766] mmc-bcm2835 fe300000.mmcnr: mmc_debug:0 mmc_debug2:0
[ 2.717878] mmc-bcm2835 fe300000.mmcnr: DMA channel allocated
[ 2.794113] mmc0: SDHCI controller on fe340000.mmc [fe340000.mmc] using ADMA
[ 2.966633] mmc1: Failed to initialize a non-removable card

vcgencmd bootloader_version
2025/09/08 15:51:29
version d179f03a2d8f83f76747c88f50cbd014132a86f4 (release)
timestamp 1757343089
update-time 1758227877
capabilities 0x0000007f

[timg236]

I suggest running lsusb -v on the host and trying RPi OS as the host.
Maybe also try lsblk on the rpiboot shell

Mmcutils are included in the boot.img if you want to run diagnostics on the mmc

[timg236]

Oh board attr says c0000000 which means it’s a lite without WiFi

[pelwell]

which means it’s a lite

The MSD support won't register as a block device unless there is onboard storage, so make sure the SD card is already fitted - this is not a card reader.