How to run linux kernel with initramfs ?

linux kernel version:4.19.217
The following part of log shows can't find root filesystem, and detail shows on attached txt file.

Then I add root filesystem folder into kernel configuration like attached pic, but it's the same error.

booting instructions,
setenv fdtaddr 0x88000000;setenv loadaddr 0x82000000;
setenv ipaddr 192.168.1.2;setenv serverip 192.168.1.1;setenv gatewayip 192.168.1.1;setenv netmask 255.255.255.0;
setenv bootargs 'console=ttyO0,115200n8 root=/dev/ram rw earlyprintk ip=192.168.1.2:192.168.1.1:192.168.1.1:255.255.255.0:POCBoard:eth0:off'
ping 192.168.1.1

tftpboot ${fdtaddr} am335x-edwards-modbus.dtb
tftpboot ${loadaddr} zImage

bootz ${loadaddr} - ${fdtaddr}

PHP Code:[2.591949]neteth0:initializingcpswversion1.12(0)
[2.707464]MicrelKSZ8081orKSZ80914a101000.mdio:00:attachedPHYdriver[MicrelKSZ8081orKSZ8091](mii_bus:phy_addr=4a101000.mdio:00,irq=POLL)
[2.731160]IPv6:ADDRCONF(NETDEV_UP):eth0:linkisnotready
[2.737507]8021q:addingVLAN0toHWfilterondeviceeth0
[4.803793]cpsw4a100000.etherneteth0:LinkisUp-100Mbps/Full-flowcontroloff
[4.813135]IPv6:ADDRCONF(NETDEV_CHANGE):eth0:linkbecomesready
[4.844436]IP-Config:Complete:
[4.847875]device=eth0,hwaddr=0c:1c:57:fa:28:52,ipaddr=192.168.1.2,mask=255.255.255.0,gw=192.168.1.1
[4.858513]host=POCBoard,domain=,nis-domain=(none)
[4.864347]bootserver=192.168.1.1,rootserver=192.168.1.1,rootpath=
[4.879241]Kernelpanic-notsyncing:VFS:Unabletomountrootfsonunknown-block(0,0)
[4.888164]---[endKernelpanic-notsyncing:VFS:Unabletomountrootfsonunknown-block(0,0)]---

Attached ThumbnailsAttached Files

my log.txt (20.2 KB)