Hi guys, I updated my tp-link 3220 from 4mb flash to 16mb flash and insaled openwrt 19, but when 3 users are connected to the WiFi router just resets so I want to go back to 17.01 but I dont know how to configure MTDPARTS in old openwrt. I found example on one device in tp-link.mk
but I dont have 128k(product-info)ro,320k(config)ro,64k(partition-table)ro,128k(logs)ro, those partitions and dont know how to tell in MTDPARTS that my art partition is at 0xff0000
If you place a copy of the ART at 0x3fffff it should run a 4 MB firmware OK, it just won't use the extra space.
At some point the AR71xx builds for TP-Link models added a bit of code (mktplinkparts.c ?) that dynamically generates the partitions at boot time based on the flash driver's reported chip size. This is still in ar71xx. You can flash such a release ar71xx directly to a unit with a larger flash chip and it will use the extra space properly.
Model-specific code in the kernel is discouraged though, so the ath79 builds do not work that way. The flash partitions are hard defined in the dts.
I suspect the crashing is due to lack of RAM if you're running more packages than the basic build, and didn't upgrade the RAM.
But you don't test it. As @mk24 said in ar7xx 17.01 release there exist mtd autopartitioning in kernel code. So you only need change firmware size value only as you did before in the related topic.
When you own-build ar71xx and want to build a ROM that is larger than 4M, you do need to increase the firmware size check value so it actually creates an image. If the final firmware ends up larger than the build system's configured chip size, it will not write out the .bin file.
If you're having crashes I'd suggest trying a release build or even stock firmware to rule out hardware problems. You can install a release build then at runtime install packages that exceed 4 MB.
Don't do that. It has known security vulnerabilities and by using it you are opening up your router and network for attacks. Try to make a lighter version of 19.07.4 by excluding things you do not need, or upgrade the router.