solo5 memory layout printout is not right about rumprun HOT 4 CLOSED

int ee_vprintf(const char *fmt, va_list args)
{
...
    n = vsnprintf(buf, PRINTF_BUF_LEN, fmt, args); // the resulting buf is not right
 ...
}

Breakpoint 3, ee_vprintf (fmt=fmt@entry=0x3254f8 "Solo5: Memory map: %llu MB addressable:\n", args=args@entry=0x1fffff70) at ee_printf.c:706
(gdb) p buf
$2 = "Solo5: Memory map: %lu MB addressable:\n", '\000' <repeats 280 times>

(gdb) p *(int *)(((char *)args[0].reg_save_area)+args[0].gp_offset)
$7 = 512
(gdb) p fmt
$8 = 0x3254f8 "Solo5: Memory map: %llu MB addressable:\n"