Helios4 SoC (Armada 388) SDIO controller supports up to UHS-I speed mode. Following modes are supported: * Default Speed (DS)–up to 25 MHz, 1.8V/3.3V signaling * High Speed (HS)–up to 50 MHz, 1.8V/3.3V signaling * SDR12–SDR up to 25 MHz, 1.8V/3.3V signaling * SDR25–SDR up to 50 MHz, 1.8V/3.3V signaling * SDR50–SDR up to 100 MHz, 1.8V signaling * DDR50–DDR up to 50 MHz, 1.8V/3.3V signaling However, it is not compatible with all cards even though the SD cards are declared as UHS-I capable. To keep it compatible with most of card, Helios4 device tree only define by default [Normal Speed mode](https://www.sdcard.org/consumers/choices/speed_class/index.html). !!! Warning Enabling High Speed and UHS-I support could lead to unbootable system because of incompatible microSD card. !!! Important From *Linux Kernel 4.19* onwards, High Speed and UHS-I modes for Helios4 do NOT work. It requires further work on our side. ## Device Tree Modification To enable High Speed mode and UHS-I support, Helios4 device tree need to be modified. The following instructions are executed under Helios4. ### Prerequisites * Helios4 Linux Kernel Source Code * Build Essentials package Install the dependencies and extract the source into ~/src/linux ``` sudo apt-get -y install build-essential linux-source-4.14.87-next-mvebu mkdir -p ~/src/linux tar Jxf /usr/src/linux-source-$(uname -r).tar.xz -C ~/src/linux ``` !!! note You will need to choose the right *linux-source* package that matches the kernel version you are running. Check kernel version with command **uname -r**. ### Patching and Compilation Download and apply [this patch](/helios4/files/sdcard/helios4_dtb_sd_uhs_linux_stable.patch) to Linux kernel source code. ``` cd ~/src/linux wget https://wiki.kobol.io/helios4/files/sdcard/helios4_dtb_sd_uhs_linux_stable.patch git apply --apply --verbose helios4_dtb_sd_uhs_linux_stable.patch ``` Compile the device tree into dtb ``` cp /boot/config-$(uname -r) .config make armada-388-helios4.dtb cp arch/arm/boot/dts/armada-388-helios4.dtb armada-388-helios4.dtb.uhs ``` !!! Info Precompiled dtb for Linux kernel 4.14 can be found [here](/helios4/files/sdcard/armada-388-helios4.dtb.uhs) Copy new dtb to /boot/dtb/, backup the original dtb and create symlink to new dtb ``` sudo cp armada-388-helios4.dtb.uhs /boot/dtb/ cd /boot/dtb/ sudo cp armada-388-helios4.dtb armada-388-helios4.dtb.ori sudo ln -sf armada-388-helios4.dtb.uhs armada-388-helios4.dtb ``` Reboot the system. ## Recovery If the system become unbootable after applying modified dtb, recover the system by [connecting to Helios4 serial console](/helios4/install/#step-4-connect-to-helios4-serial-console) and run following commands ``` setenv fdt_addr 0x2040000 setenv bootargs "console=ttyS0,115200 root=/dev/mmcblk0p1 rootwait rootfstype=ext4 ubootdev=mmc scandelay ignore_loglevel" load mmc 0:1 ${fdt_addr} /boot/dtb/armada-388-helios4.dtb.ori load mmc 0:1 ${ramdisk_addr_r} /boot/uInitrd load mmc 0:1 ${kernel_addr_r} /boot/zImage setenv fdt_high 0xffffffff setenv initrd_high 0xffffffff bootz ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr} ``` After successfully boot to Linux, restore the original dtb and remove the modified one. ``` sudo mv -f /boot/dtb/armada-388-helios4.dtb.ori /boot/dtb/armada-388-helios4.dtb sudo rm /boot/dtb/armada-388-helios4.dtb.uhs ``` ## Performance Testing The test methodology is adapted from [SD card performance - Research guides & tutorials - Armbian forum](https://forum.armbian.com/topic/954-sd-card-performance/) with slightly modified parameter to run the test on SD card mounted under /mnt/sdcard. ``` iozone -e -I -a -s 100M -r 4k -r 16k -r 512k -r 1024k -r 16384k -i 0 -i 1 -i 2 -f /mnt/sdcard/iozone-test.dat ``` To automate the test, a test script named [run_sdcard_test.sh](/helios4/files/sdcard/run_sdcard_test.sh) was created. ### Test Procedure **1.** Prepare the system to boot from SPI and Rootfs located on USB drive. See [SPI (NOR Flash) page](/helios4/spi/). **2.** Build and replace Helios4 dtb as instructed in [Device Tree Modification](#device-tree-modification). **3.** Install iozone and download the test script ``` sudo apt-get -y install iozone3 wget https://wiki.kobol.io/helios4/files/sdcard/run_sdcard_test.sh chmod 755 run_sdcard_test.sh ``` **4.** Override kernel loglevel on every boot ``` sudo sed -i 's/^exit 0/dmesg -n 8\nexit 0/g' /etc/rc.local ``` **5.** Make sure armada-388-helios4.dtb points to armada-388-helios4.dtb.uhs ``` cd /boot/dtb/ sudo ln -sf armada-388-helios4.dtb.uhs armada-388-helios4.dtb ``` **6.** Reboot and cancel U-Boot autoboot. **7.** Read SD card info and boot to Linux ``` mmc rescan mmc info bootd ``` **8.** Observe whether any error/warning on sd card detection in console and check whether sdcard is detected. ``` dmesg | grep "mmc" lsblk ``` **9.** Run the test script ``` sudo ./run_sdcard_test.sh ``` The test script will display the test progress and log result into log file : *SD_test_****\_[****]\_****.log* Example filename: SD_test_mmc0:aaaa-[SU08G]_20181212_034241.log If the SD card is not detected, the test script would exit without saving any log file. **10.** Change armada-388-helios4.dtb to point back to armada-388-helios4.dtb.ori ``` cd /boot/dtb/ sudo ln -sf armada-388-helios4.dtb.ori armada-388-helios4.dtb ``` **11.** Repeat step **6** until **9** to test in Normal Speed mode. **12.** Repeat step **5** until **11** for other card. **13.** Remove kernel loglevel override done in step **4**. ``` sudo sed -i '/^dmesg -n 8/d' /etc/rc.local ``` ### Tested MicroSD Card Below a non-exhaustive list of microSD Card models that we tested to check compatibility with UHS-I speed mode. We will keep populating this list with new microSD Card models. | **MicroSD Card Model** | **UHS-I Compatibility Result** | |--------------------|----------------| | [Kingston Mobile Card microSDHC (16GB)](#kingston-mobile-card-microsdhc-16gb)|not compatible| | [Samsung microSDHC UHS-I Card EVO Plus (32GB)](#samsung-microsdhc-uhs-i-card-evo-plus-32gb)|**yes, but no performance improvement if used as boot drive**| | [SanDisk Extreme microSDHC UHS-I Card (32GB)](#sandisk-extreme-microsdhc-uhs-i-card-32gb)|**yes, performance boosted**| | [SanDisk Extreme PRO microSDHC UHS-I Card (32GB)](#sandisk-extreme-pro-microsdhc-uhs-i-card-32gb)|**yes, performance boosted**| | [SanDisk Ultra microSD UHS-I Card (32GB)](#sandisk-ultra-microsd-uhs-i-card-32gb)|**yes, but no performance improvement**| | [SanDisk Ultra microSD UHS-I Card (16GB)](#sandisk-ultra-microsd-uhs-i-card-16gb)|not compatible| | [SanDisk Ultra microSD UHS-I Card 48MBps (16GB)](#sandisk-ultra-microsd-uhs-i-card-48mbps-16gb)|not compatible| | [SanDisk Ultra microSD UHS-I Card 30MBps (8GB)](#sandisk-ultra-microsd-uhs-i-card-30mbps-8gb)|**yes, but no performance improvement**| | [Strontium Nitro MicroSD Card (16GB)](#strontium-nitro-microsd-card-16gb)|**yes, performance boosted**| | [Toshiba MicroSD Exceria Pro (16GB)](#toshiba-microsd-exceria-pro-16gb)|not compatible| | [Transcend microSDHC Premium (8GB)](#transcend-microsdhc-premium-8gb)|**yes, but no performance improvement**| #### Kingston Mobile Card microSDHC (16GB) ![Kingston microSDHC 16GB](/helios4/img/sdcard/kingston_16gb.jpg) *Specifications* | | | | -----|------| | Product Page | [https://www.kingston.com/en/flash/microsd_cards/sdc10g2](https://www.kingston.com/en/flash/microsd_cards/sdc10g2) | | Manufacture Id | 0x00009f | | OEM ID | 0x5449 | | Product Name | SD16G | | HW Revision | 0x3 | | FW Revision | 0x0 | | Serial Number | 0x5b3003c7 | | Manufacture Date | 07/2018 | | Capacity Standard | SDHC | | SD version* | 1.0 | | Mode* | SD Legacy | | Bus Speed* | 25000000 | | Bus Width* | 4-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* : Failed! ``` mmc0: new SDHC card at address 0001 mmcblk0: mmc0:0001 SD16G 14.6 GiB mmcblk0: p1 ``` The card was detected by Linux but when the test runnning, kernel console constantly emits ``` mmcblk0: error -110 transferring data, sector 2433024, nr 1024, cmd response 0x900, card status 0xb00 mmcblk0: retrying using single block read mmc0: Timeout waiting for hardware interrupt. mmc0: sdhci: ============ SDHCI REGISTER DUMP =========== mmc0: sdhci: Sys addr: 0x00000000 | Version: 0x00000202 mmc0: sdhci: Blk size: 0x00007200 | Blk cnt: 0x00000030 mmc0: sdhci: Argument: 0x00252400 | Trn mode: 0x00000033 mmc0: sdhci: Present: 0x01e70206 | Host ctl: 0x00000011 mmc0: sdhci: Power: 0x0000000f | Blk gap: 0x00000000 mmc0: sdhci: Wake-up: 0x00000000 | Clock: 0x0000fa07 mmc0: sdhci: Timeout: 0x00000003 | Int stat: 0x00000000 mmc0: sdhci: Int enab: 0x02ff008b | Sig enab: 0x02ff008b mmc0: sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000 mmc0: sdhci: Caps: 0x25fcc8b2 | Caps_1: 0x00002f77 mmc0: sdhci: Cmd: 0x0000123a | Max curr: 0x00000000 mmc0: sdhci: Resp[0]: 0x00000900 | Resp[1]: 0x47305b30 mmc0: sdhci: Resp[2]: 0x53443136 | Resp[3]: 0x009f5449 mmc0: sdhci: Host ctl2: 0x00000008 mmc0: sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x7f0b95d0 mmc0: sdhci: ============================================ mmcblk0: error -110 transferring data, sector 2434048, nr 1024, cmd response 0x900, card status 0xb00 mmc0: Timeout waiting for hardware interrupt. ``` And the still did not finished the test after 8 hours. --- #### Samsung microSDHC UHS-I Card EVO Plus (32GB) ![Samsung EVO Plus 32GB](/helios4/img/sdcard/samsung_evo_plus_32gb.jpg) *Specifications* | | | | -----|------| | Product Page | [https://www.samsung.com/us/computing/memory-storage/memory-cards/microsdhc-evo-plus-memory-card-w--adapter-32gb--2017-model--mb-mc32ga-am/](https://www.samsung.com/us/computing/memory-storage/memory-cards/microsdhc-evo-plus-memory-card-w--adapter-32gb--2017-model--mb-mc32ga-am/) | | Manufacture Id | 0x00001b | | OEM ID | 0x534d | | Product Name | EB1QT | | HW Revision | 0x3 | | FW Revision | 0x0 | | Serial Number | 0x6d4061eb | | Manufacture Date | 06/2018 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 4-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* ``` [ 3.428116] mmc0: new high speed SDHC card at address 0001 [ 3.434040] mmcblk0: mmc0:0001 EB1QT 29.8 GiB [ 3.517590] mmcblk0: p1 [ 48.452996] mmc0: card 0001 removed [ 50.155681] mmc0: new ultra high speed DDR50 SDHC card at address 0001 [ 50.162494] mmcblk0: mmc0:0001 EB1QT 29.8 GiB [ 50.169200] mmcblk0: p1 ``` Card speed stays at high speed during boot up while other UHS-I compatible card switched to ultra high speed. It only changed to ultra high speed after remove and reinsert the card. If the card is used as boot/system drive, it is not allowed to be removed during runtime therefore no performance gain since the speed stays at high speed. ![!Samsung EVO Plus 32GB Test Result](/helios4/img/sdcard/test_result_samsung_evo_plus_32gb.png) --- #### SanDisk Extreme microSDHC UHS-I Card (32GB) ![SanDisk Extreme 32GB](/helios4/img/sdcard/sandisk_extreme_32gb.png) *Specifications* | | | | -----|------| | Product Page | [https://www.sandisk.com/home/memory-cards/microsd-cards/extreme-microsd](https://www.sandisk.com/home/memory-cards/microsd-cards/extreme-microsd) | | Manufacture Id | 0x000003 | | OEM ID | 0x5344 | | Product Name | SM32G | | HW Revision | 0x8 | | FW Revision | 0x0 | | Serial Number | 0x4313d13b | | Manufacture Date | 10/2018 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 4-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* ``` mmc0: new ultra high speed DDR50 SDHC card at address aaaa mmcblk0: mmc0:aaaa SM32G 29.7 GiB mmcblk0: p1 ``` ![!SanDisk Extreme 32GB Test Result](/helios4/img/sdcard/test_result_sandisk_extreme_32gb.png) --- #### SanDisk Extreme PRO microSDHC UHS-I Card (32GB) ![SanDisk Extreme PRO 32GB](/helios4/img/sdcard/sandisk_extreme_pro_32gb.png) *Specifications* | | | | -----|------| | Product Page | [https://www.sandisk.com/home/memory-cards/microsd-cards/extremepro-microsd](https://www.sandisk.com/home/memory-cards/microsd-cards/extremepro-microsd) | | Manufacture Id | 0x000003 | | OEM ID | 0x5344 | | Product Name | SP32G | | HW Revision | 0x8 | | FW Revision | 0x0 | | Serial Number | 0x122a8270 | | Manufacture Date | 10/2017 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 4-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* ``` mmc0: new ultra high speed DDR50 SDHC card at address e624 mmcblk0: mmc0:e624 SP32G 29.7 GiB mmcblk0: p1 ``` ![!SanDisk Extreme PRO 32GB Test Result](/helios4/img/sdcard/test_result_sandisk_extreme_pro_32gb.png) --- #### SanDisk Ultra microSD UHS-I Card (32GB) ![SanDisk Ultra smartphone 32GB](/helios4/img/sdcard/sandisk_ultra_uhs-i_for_smartphone_32gb.jpg) *Specifications* | | | | -----|------| | Product Page | [https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-for-smartphones](https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-for-smartphones) | | Manufacture Id | 0x000003 | | OEM ID | 0x5344 | | Product Name | SL32G | | HW Revision | 0x8 | | FW Revision | 0x0 | | Serial Number | 0x0c9daa71 | | Manufacture Date | 04/2014 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 4-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* ``` mmc0: new ultra high speed DDR50 SDHC card at address aaaa mmcblk0: mmc0:aaaa SL32G 29.7 GiB mmcblk0: p1 mmc0: Tuning failed, falling back to fixed sampling clock mmcblk0: error -84 transferring data, sector 62333824, nr 8, cmd response 0x900, card status 0xb00 ``` Even though there are some errors, the test finished without much improvement. ![!SanDisk Ultra smartphone 32GB Test Result](/helios4/img/sdcard/test_result_sandisk_ultra_uhs-i_for_smartphone_32gb.png) --- #### SanDisk Ultra microSD UHS-I Card (16GB) ![SanDisk Ultra smartphone 16GB](/helios4/img/sdcard/sandisk_ultra_uhs-i_for_smartphone_16gb.jpg) *Specifications* | | | | -----|------| | Product Page | [https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-for-smartphones](https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-for-smartphones) | | Manufacture Id | 0x000003 | | OEM ID | 0x5344 | | Product Name | SL16G | | HW Revision | 0x8 | | FW Revision | 0x0 | | Serial Number | 0xa5253c77 | | Manufacture Date | 04/2017 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 4-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* : Failed! ``` mmc0: new ultra high speed DDR50 SDHC card at address aaaa mmcblk0: mmc0:aaaa SL16G 14.8 GiB mmcblk0: error -84 sending status command, retrying mmc0: Tuning failed, falling back to fixed sampling clock mmcblk0: error -84 sending status command, retrying mmc0: Tuning failed, falling back to fixed sampling clock mmcblk0: error -84 sending status command, aborting mmc0: Tuning failed, falling back to fixed sampling clock mmcblk0: unable to read partition table mmc0: card aaaa removed mmc0: new high speed SDHC card at address aaaa mmcblk0: mmc0:aaaa SL16G 14.8 GiB mmcblk0: error -84 sending status command, retrying mmcblk0: error -84 sending stop command, original cmd response 0x900, card status 0x900 mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0x0 mmcblk0: error -84 sending stop command, original cmd response 0x900, card status 0x900 mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0x0 ``` The card was not detected by Linux. --- #### SanDisk Ultra microSD UHS-I Card 48MBps (16GB) ![SanDisk Ultra 48MBps](/helios4/img/sdcard/sandisk_ultra_uhs-i_48mbps_16gb.jpg) *Specifications* | | | | -----|------| | Product Page | [https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-48mbs](https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-48mbs) | | Manufacture Id | 0x000003 | | OEM ID | 0x5344 | | Product Name | SL16G | | HW Revision | 0x8 | | FW Revision | 0x0 | | Serial Number | 0x349f2b91 | | Manufacture Date | 01/2016 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 4-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* : Failed! ``` mmc0: new ultra high speed DDR50 SDHC card at address aaaa mmcblk0: mmc0:aaaa SL16G 14.8 GiB mmc0: Tuning failed, falling back to fixed sampling clock mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0xb00 mmcblk0: p1 mmcblk0: error -84 transferring data, sector 10240, nr 8, cmd response 0x900, card status 0xb00 mmcblk0: error -84 transferring data, sector 8784, nr 72, cmd response 0x900, card status 0xb00 mmcblk0: error -84 transferring data, sector 8784, nr 72, cmd response 0x900, card status 0xb00 mmcblk0: retrying using single block read mmcblk0: error -84 transferring data, sector 8856, nr 360, cmd response 0x900, card status 0xb00 mmcblk0: error -84 transferring data, sector 8856, nr 360, cmd response 0x900, card status 0xb00 ``` The card was not detected by Linux. --- #### SanDisk Ultra microSD UHS-I Card 30MBps (8GB) ![SanDisk Ultra 30 MBps](/helios4/img/sdcard/sandisk_ultra_uhs-i_8gb.jpg) *Specifications* | | | | -----|------| | Product Page | [https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-for-smartphones](https://www.sandisk.com/home/memory-cards/microsd-cards/ultra-microsd-for-smartphones) | | Manufacture Id | 0x000003 | | OEM ID | 0x5344 | | Product Name | SU08G | | HW Revision | 0x8 | | FW Revision | 0x0 | | Serial Number | 0x2369e07f | | Manufacture Date | 12/2013 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 4-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* ``` mmc0: new ultra high speed DDR50 SDHC card at address aaaa mmcblk0: mmc0:aaaa SU08G 7.40 GiB mmc0: Tuning failed, falling back to fixed sampling clock mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0xb00 mmcblk0: p1 ``` Even though there are some errors, the test finished. Many of test cases see performance reduction. ![!SanDisk Ultra 30 MBps Test Result](/helios4/img/sdcard/test_result_sandisk_ultra_uhs-i_8gb.png) --- #### Strontium Nitro MicroSD Card (16GB) ![Strontium](/helios4/img/sdcard/strontium_nitro_16gb.jpg) *Specifications* | | | | -----|------| | Product Page | [http://www.strontium.biz/products/memory-cards/mobile-memory-cards/#seven](http://www.strontium.biz/products/memory-cards/mobile-memory-cards/#seven) | | Manufacture Id | 0x000084 | | OEM ID | 0x5446 | | Product Name | SD | | HW Revision | 0x0 | | FW Revision | 0x0 | | Serial Number | 0x954b266b | | Manufacture Date | 09/2016 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 1-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* ``` mmc0: Tuning failed, falling back to fixed sampling clock mmc0: new ultra high speed DDR50 SDHC card at address 0001 mmcblk0: mmc0:0001 SD 14.6 GiB mmcblk0: p1 mmc0: Tuning failed, falling back to fixed sampling clock mmc0: Tuning failed, falling back to fixed sampling clock ``` Even though there are some warnings, the test finished. ![!Strontium Nitro Test Result](/helios4/img/sdcard/test_result_strontium_nitro_16gb.png) --- #### Toshiba MicroSD Exceria Pro (16GB) ![Toshiba Exceria Pro](/helios4/img/sdcard/toshiba_exceria_pro_16gb.jpg) *Specifications* | | | | -----|------| | Product Page | [https://www.toshiba-memory.com/products/toshiba-microsd-cards-exceria-pro-m401/](https://www.toshiba-memory.com/products/toshiba-microsd-cards-exceria-pro-m401/) | | Manufacture Id | 0x000002 | | OEM ID | 0x544d | | Product Name | UC0C5 | | HW Revision | 0x5 | | FW Revision | 0x0 | | Serial Number | 0xd2a0e6a3 | | Manufacture Date | 11/2016 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 4-bit | !!! Notes * Value taken from U-Boot "mmc info". *Test Result* : Failed! ``` mmc0: error -84 whilst initialising SD card ``` The card was not detected by Linux. --- #### Transcend microSDHC Premium (8GB) ![Transcend](/helios4/img/sdcard/transcend_premium_8gb.jpg) *Specifications* | | | | -----|------| | Product Page | [https://www.transcend-info.com/Products/No-320](https://www.transcend-info.com/Products/No-320) | | Manufacture Id | 0x000074 | | OEM ID | 0x4a45 | | Product Name | USD | | HW Revision | 0x1 | | FW Revision | 0x0 | | Serial Number | 0x4568e585 | | Manufacture Date | 06/2014 | | Capacity Standard | SDHC | | SD version* | 3.0 | | Mode* | SD High Speed (50MHz) | | Bus Speed* | 50000000 | | Bus Width* | 1-bit | *Test Result* ``` mmc0: new high speed SDHC card at address b368 mmcblk0: mmc0:b368 USD 7.45 GiB mmcblk0: p1 ``` ![!Transcend Premium Test Result](/helios4/img/sdcard/test_result_transcend_premium_8gb.png) --- **Value taken from U-Boot "mmc info"*