There were more encouraging signs from David Weir's Blades, netting three second half goals to secure another pre-season friendly.
In blistering sunshine at Bury, against former Blades boss Kevin Blackwell, United hit back from a goal down at half-time to win.
Jasper Johns netted with his second touch, Jamie Murphy added the second and then Stephen McGinn also notched his first in a Blades shirt.
Flynn, Johns and Kennedy featured on a David Weir teamsheet for the first time but only the latter started at Gigg Lane and from his right-back position he attempted a pot-shot on three minutes which wasn't far wide. Earlier, a run from Smith was promising but his shot was blocked by Hinds.
Also in first 15 minutes Higginbotham curled a free-kick wide, whilst at the other end Howard had to off his line quickly to deny Harrad and the goalkeeper tipped over from Holden.
United were continuing with the passing policy but a stray forward ball from McGinty gave Bury the opportunity to counter on 20 minutes and HARRAD was clinical with his finish from the edge of the box to give the home side the lead.
Teenager Smith looked lively for United, he beat Hinds on 29 minutes before being bundled over by Dikamona but no penalty was forthcoming and Harrad twice went close to adding to his tally in the same move but he was denied by Kennedy and Howard.
Bury were on the offensive late in the first half but Howard and his defence repelled further efforts and both sides would have been delighted to hear the half-time whistle to get out of the burning sun.
With Howard stranded, Grimes had a chance to double Bury's lead but he shot wide early in the second half and for United, Ironside cut in from the left but scuffed his shot.
Around the hour mark, boss Weir made six changes - introducing Collins, Maguire, Williams, Johns, McDonald and Porter - and it immediately paid dividends with two of the replacements linking up to level the scores. McDonald delivered a deep cross from the right and JOHNS would have scored with his first ever Blades touch had his original effort not been cleared off the line by Hinds but the new boy poked home the rebound.
Brandy's last involvement before being taken off was to cause problems in the Bury boss but Byrne kicked away and then the striker's replacement, Murphy, went close with his first effort after coming on.
The Blades were looking lively in the second half, despite the chances, and took the lead on 78 minutes with another encouraging move. McDonald's accurate ball to the right found MURPHY, who got the better of Byrne and chipped over the advancing goalkeeper, although he was helped by a deflection.
The icing was put on the victory with an excellent goal on 88 minutes. Williams delivered a deep cross from the left and McGINN sidefooted a volley into the top corner, giving Bury substitute goalkeeper Guatelli little chance.
Bury: Lainton, Dikamona, Roberts, Holden, Hinds, Cameron, Jones, Randall, Harrad, Grimes, Chippendale.
Subs: Lockwood, Procter, Byrne, Soares, Sedgwick, Rooney, Pratt, Guatelli.
Blades: Howard, Kennedy (Westlake 45), Higginbotham (Maguire 60), McGinty (Collins 60), Hill (Williams 60), Whitehouse, Doyle (McGinn 45), Brandy (Murphy 66), Smith (McDonald 60), McFadzean (Johns 60), Ironside (Porter 60).
Unused: Willis, Flynn.