As mentioned above - getting a Himalayan produced for the asian marked registred in Bosnia might be a problem. Bosnia is still not a member of the EU but afaik in negotiationes about entering (?) So it will be the same rules as Noraly AKA Itchy Boots faced when she tried to get her Himalayan registred in Netherland - not type approved for the EU and thus not possible to register.
But the best source of information about this is the traffic authorities in your home country.

A couple of other things:

1. There is no international bordercrossing between Laos and Myanmar. Its only a local bordercrossing for Laos and Myanmar citizens. Theres been talk about upgrading it to an international bc and Myanmar has actually prepared for that, but Laos has not. So you will have to travel through Thailand.
And Thailand do not like vietnamese plated bikes so you will most probably need the mandatory and costly permits and guides that Thailand demands of foreign vehicles in their country.
A tip - it should be possible to ride from Huay Xai/Chiang Khong (Lao/thai border) to the Mae Sot-Myawaddy bordercrossing in one longish day to reduce costs. Or if you could cross into Myanmar at Mae Sai-Tachilek it would be even better as its only approx 100 kms from Huay Xai-Chiang Khong.

2. Myanmar also demands these mandatory guides and permits, absolutely no way around. Join a group or form one yourself to reduce costs.

Best of luck with your trip!

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In the end everything will be fine. If its not fine its not the end....