sceGeEdramSetSize not working properly

Hello, I'm trying to use sceGeEdramSetSize(0x400000) to increase the vram but it's not working on my PSP Street.
Any idea why this code doesn't work?
Thanks!

#include <string>
#include <pspkernel.h>
#include <pspdisplay.h>
#include <pspge.h>

PSP_MODULE_INFO("PSP VRAM ISSUE", 0, 1, 0);
PSP_MAIN_THREAD_ATTR(THREAD_ATTR_USER);

int main(int argc, char *argv[])
{
    pspDebugScreenInit(); // Initialize the debug screen

    if (sceGeEdramSetSize(0x400000) == 0)
    {
        pspDebugScreenPrintf("sceGeEdramSetSize 4MB ok\n"); // Never called
    }
    else
    {
        pspDebugScreenPrintf("sceGeEdramSetSize 4MB ERROR\n"); // Called
    }

    pspDebugScreenPrintf(std::to_string(sceGeEdramGetSize()).c_str()); // Prints "2097152" instead of the double

    while (true)
    {
        sceDisplayWaitVblankStart();
    }
}

Start by reproducing the shown C++ program on a PSP Street and inspect the return values from sceGeEdramSetSize and sceGeEdramGetSize. Check the PSP SDK declarations and documentation for these entry points and compare the requested size with the device's reported behavior. Done means the platform-specific behavior and any required conditions are established and documented.