eMMC to SD card adapter doesn't work

I did purchase the RockPi 4 with 16GB eMMC and adapter. When I want to flash the image on eMMC with the adapter it does not recognize the flash memeory.

I can say, I am lucky, since I own HardKernel’s MicroSD adapter from my previous device Odroid C2. Well this adapter works and the image was flashed.

So, why the official SD card adapter doesn’t work? Who is going to send me a functional one?

Try opening windows device manager and plugin the adapter with emmc attached , see if you can find it there

No, it doesn’t work. As said the HardKernel apapter works, no problems. Raspberry SD card works, no problem. Your adapter doesn’t work. I have to mount your’s eMMC onto a HardKernel’s adapter to be able to flash or read.

Same here… Had to flash the eMMC directly connected to the RockPi 4 and later I bought the USB adapter instead.

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My EMMC adapter worked fine. But you can also boot from SD and then mount the EMMC (with the EMMC mounted on the Rock Pi, not using the SD adapter).

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I had the same issue when I purchased 3 Rock Pi 4B’s with the eMMC reader. It simply does not work. I’ve tried multiple SD adapters and methods of connecting and nothing. Judging by this thread it sounds like they have a high failure rate. I raised the issue with support nearer the time of purchase but after they got me to jump through a bunch of hoops to prove it was faulty i.e. sending pictures, writing descriptive text of my methods, posting it back to China, I lost interest as it wasn’t worth my time over a $3 piece of nothing. The Rock Pi freezes when I try to dd an image from the OS (booted via SD) to the eMMC so my next attempt will be to find a USB A to USB A cable and install the the eMMC via OTG. The fact that this cheap little eMMC reader hasn’t worked has wasted a lot of my time.

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I have the same issue.
Here’s what worked for me - purchased an $11.99 16GB micro ssd; format, load new OS THEN viola “works”.

What I noticed is that the eMMC to uSD adapter does not work on the Rock Pi 4 itself. Get the following in dmesg:

[  872.743749] vcc_sd: unsupportable voltage range: 3300000-3000000uV
[  872.744374] rockchip-iodomain ff770000.syscon:io-domains: Setting to 3000000 done
[  872.745055] rockchip-iodomain ff770000.syscon:io-domains: Setting to 3000000 done
[  872.785761] vcc_sd: unsupportable voltage range: 3300000-3000000uV
[  872.786387] rockchip-iodomain ff770000.syscon:io-domains: Setting to 3000000 done
[  872.787067] rockchip-iodomain ff770000.syscon:io-domains: Setting to 3000000 done
[  872.803764] mmc_host mmc0: Bus speed (slot 0) = 300000Hz (slot req 300000Hz, actual 300000HZ div = 0)
[  872.830857] vcc_sd: unsupportable voltage range: 3300000-3000000uV
[  872.831558] rockchip-iodomain ff770000.syscon:io-domains: Setting to 3000000 done
[  872.832237] rockchip-iodomain ff770000.syscon:io-domains: Setting to 3000000 done
[  872.847735] mmc_host mmc0: Bus speed (slot 0) = 200000Hz (slot req 200000Hz, actual 200000HZ div = 0)
[  872.877446] vcc_sd: unsupportable voltage range: 3300000-3000000uV
[  872.878053] rockchip-iodomain ff770000.syscon:io-domains: Setting to 3000000 done
[  872.878731] rockchip-iodomain ff770000.syscon:io-domains: Setting to 3000000 done
[  872.895696] mmc_host mmc0: Bus speed (slot 0) = 100000Hz (slot req 100000Hz, actual 100000HZ div = 0)

It works on my laptop though running Linux:

[108382.264655] mmc0: new high speed MMC card at address 0001
[108382.265548] mmcblk0: mmc0:0001 SOD16G 14.6 GiB 
[108382.265723] mmcblk0boot0: mmc0:0001 SOD16G partition 1 4.00 MiB
[108382.265877] mmcblk0boot1: mmc0:0001 SOD16G partition 2 4.00 MiB
[108382.277936]  mmcblk0: p1 p2 p3 p4 p5
[108424.072301] mmc0: card 0001 removed
[108465.766913] mmc0: new high speed MMC card at address 0001
[108465.767144] mmcblk0: mmc0:0001 SOD16G 14.6 GiB 
[108465.767262] mmcblk0boot0: mmc0:0001 SOD16G partition 1 4.00 MiB
[108465.767371] mmcblk0boot1: mmc0:0001 SOD16G partition 2 4.00 MiB
[108465.778398]  mmcblk0: p1 p2 p3 p4 p5

These sorts of things tend to have a lot of problems with SD Card adapters; I’ve had failures with the Hardkernel, FriendlyArm and Radxa units when trying to use them through an uSD->SD adapter, but using them direct in the slot of a multicard->USB adapter (with dedicated uSD slot), they worked properly.

I never used uSD->SD adapter, I have always plugged directly, but it doesn’t work on PC and on RockPi neither.

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