Tyring to give answers to your comments in one post:
Yes I already picked the MIPSBE (all my boxes are same arch). I don't want to do a netinstall, because my goal is precisly to test upgrade process on mAP-Lite before doing it on the rest of my oards to check the current configuration is kept/migrated and foreseen any potential issues.
Absolutely first thing one should be checking after failed upgrade is logs ... most of times one of first log entries contains a clue as to what went wrong.
Due the low storage capacity I have logging to disk disabled, however just after the reboot is confirms my fears:
12:59:37 system,info installed system-7.2.1
12:59:37 system,error not enough space for upgrade
There are plenty of other devices having the same amount of flash being perfectly capable of running ROS7.
It is true you need to assess if you want to use the new features from ROS7 and if you are willing to accept some other things might not work fully or not at all yet. Especially with the advanced routing stuff, there are quite some errrm ... "opportunities for improvement" (to put it positively) but I would think those are not target processes to be used on a mAP Lite.
I have ROS7 on a mAPLite since mid last year, normal upgrade from ROS 6 to ROS 7, and never had any problems with it for the use cases I have with that device (Road Warrior device with station mode wlan, virtual wlan AP and Wireguard VPN to home).
Right, I seen many other (newer) devices with the same storage capacity (16MiB) so that's why I asked
I'm not too much worried on any 'advanced' stuff, the most I use are some simples VLANs and BGP.
At least is good to know somebody achieved to upgrade to 7 even using some of the features I am using. I would really appreaciate if you can share the config as I also use it as RoadWarrior in similar setup (VLANs and VPN).
A lot has been said here so far but no one has mentioned the fact that 7.x always uses the bundle package, so if some packages are not installed in the current 6.x installation, the upgrade will fail. I'm not sure whether it is enough to install the missing packages in 6.x or whether only "full 6.x bundle to 7.x bundle" upgrade is possible, nor whether you can upgrade from a complete set of individual 6.x packages to a 6.y (y>x) bundle. What I do know, though, is that recent 6.x versions are smaller than older ones, so even those resource-limited devices can be upgraded using bundles again. So if netinstall is complicated for you, it is worth trying to upgrade to 6.48.x (x<6), install the missing packages, and then trying to upgrade to 7.2.1; if that still doesn't work, try to upgrade to a 6.48.6 bundle first.
Really interesting, as the first thing I realized is that 7 is bundled differently (at least on base/extra stuff)
I already used netinstall in the past, but as said before my goal is precisely test the upgrade process.
I upgradde from 6.48 to 6.49.6 wihtout issues, but when tried upgrade to 7 I faced same problems, I think related to what you comment.
I tried to remove some of the installed packages to reduce the size used, but although small (I only left system,dhcp and wireless), it still reports only 3MiB of 16MiB are free (even withhout logging, DNS-cache or proxy and nothing in files). After trying to upgrade I get:
12:59:37 system,error broken package wireless-7.2.1-mipsbe.npk
12:59:37 system,error broken package dhcp-7.2.1-mipsbe.npk
12:59:37 system,error broken package security-7.2.1-mipsbe.npk
12:59:37 system,error broken package ppp-7.2.1-mipsbe.npk
12:59:37 system,error broken package ntp-7.2.1-mipsbe.npk
12:59:37 system,error broken package advanced-tools-7.2.1-mipsbe.npk
12:59:37 system,error broken package routing-7.2.1-mipsbe.npk
12:59:37 system,info installed system-7.2.1
12:59:37 system,error not enough space for upgrade
Indeed sems is looking for the same packages I'm using on 7.2, however they are not now bundled in the base packages. Also note it also complains about not enough space for upgrade