[U-Boot] How to validate ext4load file size (not null)?

I have stored multiple device trees in my emmc (ext4 formatted) partition and I want to load a certain device tree file from emmc, but if this fails (i.e. the device tree file doesn't exist) it should default to a device tree that is stored in memory. For example if I run this: I get a return

[U-Boot] How to validate ext4load file size (not null)?

I have stored multiple device trees in my emmc (ext4 formatted) partition and I want to load a certain device tree file from emmc, but if this fails (i.e. the device tree file doesn't exist) it should default to a device tree that is stored in memory. For example if I run this: I get a return