
558 S.E.2d 787 (2002)
253 Ga. App. 238
BOYD
v.
The STATE.
No. A01A2525.
Court of Appeals of Georgia.
January 11, 2002.
Larry J. Boyd, pro se.
Robert E. Keller, Dist. Atty., for appellee.
BARNES, Judge.
Larry Boyd, pro se, appeals the trial court's order denying his motion to vacate, set aside, modify, or correct "a null and void sentence." The record shows that in 1995, this court affirmed Boyd's conviction for armed robbery in an unpublished opinion. Boyd v. State, 219 Ga.App. XXVI (1995). On April 16, 2001, Boyd filed this motion, which the trial court denied April 24, 2001. He appeals, arguing that he should not have received a life sentence following a jury trial, but should have been allowed to plead guilty with a court-approved sentence of ten years.
*788 Although he contends that he is challenging an illegal sentence, Boyd's appeal, in fact, attacks only the rejection of his negotiated guilty plea. This is not an attack on his sentence, and, even if his allegations were true, they would not make his sentence void. "A sentence is void if the court imposes punishment that the law does not allow." Crumbley v. State, 261 Ga. 610, 611(1), 409 S.E.2d 517 (1991). Therefore, Boyd's motion was properly denied.
Further, in an appeal in which jurisdiction depends on a challenge to an allegedly void sentence, Boyd may not raise issues which only involve the validity of his conviction. Daniels v. State, 244 Ga.App. 522, 523, 536 S.E.2d 206 (2000). Therefore, as this appeal is not an attack on a void sentence, we are without jurisdiction to consider it. Such "bootstrapping" cannot vest this court with jurisdiction to consider potential errors that should have been asserted in Boyd's direct appeal. Davis v. State, 233 Ga.App. 825, 826-827, 505 S.E.2d 801 (1998); Balkcom v. State, 227 Ga.App. 327, 331-332, 489 S.E.2d 129 (1997).
Further, Boyd should have asserted this alleged error in his prior appeal, and by not asserting the error at that time, he waived or abandoned appellate consideration of the issue. See Bellamy v. Fed. Deposit Ins. Corp., 236 Ga.App. 747, 750(c), 512 S.E.2d 671 (1999). Therefore, he cannot raise the issue in a later appeal because of res judicata. Blalock v. State, 201 Ga.App. 461, 411 S.E.2d 914 (1991). Appellants cannot present a portion of their claim in one appeal and reserve other issues in the event the first claim fails, because appeals cannot be relitigated ad infinitum. See Echols v. State, 243 Ga.App. 775, 776, 534 S.E.2d 464 (2000).
Accordingly, we have no jurisdiction to consider this appeal.
Appeal dismissed.
SMITH, P.J., and PHIPPS, J., concur.
