Bleichenbacher RSA1024 signature forgery, closed-form solution

Hal Finney's writeup (Bleichenbacher's RSA signature forgery based on implementation error) shows a formula for RSA3072. I tried to replicate the attack for RSA1024 and failed, since the first term of the equation 2^1009 is not a perfect cube. I ended up forging a signature by simply constructing a desired number and taking cube root of it. But I'm curious, is it possible to come up with a clean formula, as in the case of RSA3072?