In 1420-21, he started building and repairing forts and establishing military outposts to strengthen state from attacks. He built the forts of Dahod on the Malwa frontier and of Jitpur in Lunawada. In 1421 he repaired the fort in the town of Kahreth, otherwise called Meimun in Lunavaḍa, which had been built by Ulugh Khan Sanjar in the reign of Sultan Ala-ud-din Khalji and changed the name to Sultanpur. In December 1421, he advanced against Malwa and took the fort of Mesar. He attacked and received tributes from other border states before he reached Mandu in March 1422. Hushang Shah was in Jajnagar (Orissa) at that time. After 48 days of unsuccessful siege and several clashes, Ahmad Shah had to moved to Ujjain in May due to incoming monsoon. He again imposed siege in September 1421 but Hushang Shah had returned to Mandu with large number of war elephants from Orissa. Ahmad Shah left Mandu knowing that it would be difficult to win. He moved and camped Sarangpur when he was reached by ambassadors sent by Hushang Shah for treaty of peace. Ahmad Shah agreed but, on the night of 26 December 1421, an army of Hushang Shah attacked the camp. Ahmad Shah repelled the attack but had to endure heavy casualty. Hushang Shah took refuge in fort of Sarangpur. Ahmad Shah again laid siege to Sarangpur. Failing to take the fort, Ahmad Shah decided to return Ahmedabad on 7 March 1423 but he was chased by an army of Hushang Shah. Both armies met and after fierce battle, Ahmad Shah won. He returned to Ahmedabad on 23 May 1423.