Supposedly, all motherboards marked Ryzen 2000 Ready have Bios that will work "out of the Box" with all Ryzen 2000 series (7, 5, G) CPUs. That being said I had a bad experience with an ASRock X370 PRO4 AM4 motherboard which is listed as Ryzen 2000 Ready on newegg.com and the box itself. I think AMD got motherboard vendors to change their boxes on stock that was shipping with BIOS that support all Ryzen 2000 chips. I couldn't get this board to boot with a Ryzen 2200G CPU with or without discrete GPU, until I upgrade the BIOS. Luckily, I have an Ryzen 1700 system which I pulled the CPU out of which wasn't fun since it is watercooled. I'm not convince that the CPU was the cause of the non-booting... I was using 2 x 16GB Trident Z 3000 CL14 (pulled from my Ryzen 1700, which had four in total) memory modules. When the Ryzen 2200G was installed it with Original Bios (4.50, which state they support all Ryzen chips including 2000s) the CPU fan would spin for awhile then stop and then repeat endlessly. So maybe there is an issue just with the 2200G, my memory used and the 4.50 bios. It booted no problem with the Ryzen 1700, 4.50 bios and same memory however. I upgraded the BIOS to 4.70 and then put the 2200G back in and it worked, but I'm RMAing it because if I hooked more than 3 GPUs (I was going to using it for Ethereum mining), no booty, booty even after going back to one card I would have to CLEAR CMOS to even get it to boot.
Actually not sure why Asrock bothered with this mobo. It is an X370 chipset, but they only wired the 2nd 16x PCIe slot with 4 lanes, so it is nearly identical in features to their B350 motherboard. I also won't be using the 2200G for mining, since I think the PCIe lanes on it (only half the lanes of a non-G Ryzen) limit its use with any X370 board. It was just a stop-gap any how, since I pulled the 2200G from a HTPC build) when my actual mining CPU/Motherboard (FX8320/990FX) died.
Long Story Short, Motherboards with box marked Ryzen 2000 Ready is supposed to support ALL Ryzen 2000 CPUSs.
Yes, I noticed that with the ASRock boards on Newegg but looked through and saw some bad reviews of people P.O. that the board wouldn't boot and they had to do exactly what you did. I wasn't willing to go the ASRock route just because between AMD, board makers and the retailers they couldn't get their S@#^ together. As much as it may be a retailer/board manufacturer issue, AMD would be wise as it has to do with their launched products. They really should find a way to take some more initiative to make this a non-issue for customers. Heck, even reach out to small I.T. shops around the country like mine, make us a sort of partner or something and allow us to flash peoples BIOS at no charge to the customer and they give us a free CPU for that purpose and maybe $5-$10 per each board we flash. They would have saved that much in shipping, extra products and lost sales. Show you have a support network around your products and people would be more likely to buy into your platform.