How to detect the RAM Vendor


with a new TX2 module I noticed a new revision of the module. Revision D01 instead of B02. The image is based on R28.1.

According to PCN (PCN204840) the RAM (or better to say the BOM) has been changed and the module may contain the old RAM IC or the new one from Hynix.
Is it possible to detect the vendor of the RAM based on the serial number or with a command? I tried with dmidecode first, but it doesn’t work properly.

Hi aleksej.lazarev,

May I know why need to get this information? If there any different behavior or performance on D01 by compared with B02?


Hi Kayccc,

I didn’t notice any different behavior or performance so far. I have to perform several tests. According to PCN [1] and the section “Recommended Action for Customer” (Page 3), R28.1 do not contain the required BCT and DVFS. For me it sounds like I would operate the module out of specs (wrong timing, wrong voltages?) and behavior like crashes or similar errors can be expected if I don’t switch to R28.2.


From PCN document:



Hi Kayccc,

We have the same question as aleksej.lazarev.
How to support the following features on TX2 R27.1 and R28.1?
o appropriate BCT and DVFS changes required by the Hynix memory device
o appropriate BCM4354 firmware changes required by the RF360 band edge filter


Hi kayccc,

any updates on this topic?

It is my understanding that the BootRom configures the memory according to the sdram config used when flashing and the ram code that indexes into that config. The BootRom then exposes this data to the kernel. The sdram config file used when flashing P3310_A00_8GB_Samsung_8GB_lpddr4_204Mhz_A02_l4t.cfg has a new entry (index 2) for later L4T releases supporting the Hynix memory. The ram code can be accessed in the kernel via the function tegra_read_ram_code().

We have not yet validated that this is the only necessary change for a 28.1-based release to support the new memory.

Below debugfs will help in getting manufacturer info

root@tegra-ubuntu:/home/ubuntu# cat /sys/kernel/debug/bpmp/debug/emc/dram_info
Manufacturer ID (MR5): 255
Revision ID-1 (MR6): 0
Revision ID-2 (MR7): 1
IO Width/Density/Type (MR8): 0x10